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Safety and Immunogenicity of a Candidate Parvovirus B19 Vaccine
Abstract
Parvovirus B19 is an important human pathogen causing erythema infectiosum, transient aplastic crisis in individuals with underlying hemolytic disorders and hydropsfetalis. We therefore evaluated a parvovirus B19 virus like particle (VLP) vaccine. The safety and immunogenicity of a 25 μg dose of parvovirus B19 recombinant capsid; 2.5 and 25 μg doses of the recombinant capsid given with MF59; and saline placebo were assessed in healthy adults. Because of 3 unexplained cutaneous events the study was halted after enrollment of 43 subjects and before any subject received their third scheduled dose. The rashes developed 5-9 days after the first or second injection and were seen in one placebo recipient (without an injection site lesion) and two vaccine recipients (with injection site reactions). No clear cause was established. Other safety evaluations revealed mostly injection site reactions that were mild to moderate with an increase in pain in subjects receiving vaccine and MF59. After dose 2 the majority of vaccine recipients developed ELISA and neutralizing antibody to parvovirus B19. Given the possible severe consequences of parvovirus B19 infection, further development of a safe and effective vaccine continues to be important.
... The particles not pure, had intact phospholipase A2 activity, and had variable VP1:VP2 ratios. In s immunized subjects, rashes appeared near the injection site [18]. Hypotheses for the c of the reactogenicity focused on VLP impurities and PLA2 activity. ...
... The particles were not pure, had intact phospholipase A2 activity, and had variable VP1:VP2 ratios. In some immunized subjects, rashes appeared near the injection site [18]. Hypotheses for the cause of the reactogenicity focused on VLP impurities and PLA 2 activity. ...
... In culture, parvovirus B19 only infects human erythroid progenitor cells (EPCs); cytotoxicity for these progenitors abrogates erythroid Vaccines 2021, 9, 860 3 of 13 colony formation in vitro. Cell substrates used for parvovirus B19 neutralization assays include the UT7/Epo-S1 cell line, EPCs generated ex vivo from human hematopoietic stem cells, and EPCs differentiated and expanded from human peripheral blood mononuclear cells (PBMCs) [18,19]. The read out of the assay is detection of parvovirus B19 RNA transcripts by quantitative reverse-transcription polymerase chain reaction. ...
Children with sickle cell disease (SCD) suffer life-threatening transient aplastic crisis (TAC) when infected with parvovirus B19. In utero, infection of healthy fetuses may result in anemia, hydrops, and death. Unfortunately, although promising vaccine candidates exist, no product has yet been licensed. One barrier to vaccine development has been the lack of a cost-effective, standardized parvovirus B19 neutralization assay. To fill this void, we evaluated the unique region of VP1 (VP1u), which contains prominent targets of neutralizing antibodies. We discovered an antigenic cross-reactivity between VP1 and VP2 that, at first, thwarted the development of a surrogate neutralization assay. We overcame the cross-reactivity by designing a mutated VP1u (VP1uAT) fragment. A new VP1uAT ELISA yielded results well correlated with neutralization (Spearman’s correlation coefficient = 0.581; p = 0.001), superior to results from a standard clinical diagnostic ELISA or an ELISA with virus-like particles. Virus-specific antibodies from children with TAC, measured by the VP1uAT and neutralization assays, but not other assays, gradually increased from days 0 to 120 post-hospitalization. We propose that this novel and technically simple VP1uAT ELISA might now serve as a surrogate for the neutralization assay to support rapid development of a parvovirus B19 vaccine.
... Vaccine developmentBallou et al., (2003) showed that vaccines for animal parvovirus's and parvovirus B19 infection have the same efficiency , the recombinant immunogenic that used as a vaccine for the human virus lack DNA, therefore non-infectious . Viral capsid has been planned as general vehicles for the release of antigens , B19V is particularly attractive for this point, because the VP1 unique region can be completely replaced with other protein sequences( Miyamura et al ., 1994 ). is modified exclusively to human host , transmitted by through interpersonal contact and efficiently neutralized by the immune response , introduction and development of a vaccine mostly to protect populations at risk such as patients with underlying hematological disorders(Bernstein et al ., 2011) .Women of reproductive age will benefit from vaccine protection, specifically for fetal safety . The main immunological determinants are viral capsule proteins , with their VP2 conformational and VP1u linear epitopes( Bernstein et al ., 2011) . ...
... Viral capsid has been planned as general vehicles for the release of antigens , B19V is particularly attractive for this point, because the VP1 unique region can be completely replaced with other protein sequences( Miyamura et al ., 1994 ). is modified exclusively to human host , transmitted by through interpersonal contact and efficiently neutralized by the immune response , introduction and development of a vaccine mostly to protect populations at risk such as patients with underlying hematological disorders(Bernstein et al ., 2011) .Women of reproductive age will benefit from vaccine protection, specifically for fetal safety . The main immunological determinants are viral capsule proteins , with their VP2 conformational and VP1u linear epitopes( Bernstein et al ., 2011) . ...
ParvovirusB19 is pathogenic virus for human , ass-DNA member of the family Parvoviridae, characterized by a selective tropism for erythroid progenitor cells (EPCs) in the bone marrow. Persistent B19 infection may manifest as pure red cell aplasia and chronic anemia and tends to occur in immune compromised hosts.
The study included (100 sample) of lymphoma patients suffering from anemia and receiving chemotherapy. In addition, 100 sample lymphoma patients without anemia were included as control group . Serum B19 immunoglobulin G and IgM levels were examined by an ELISA technique, the results showed that the highest seropositivity of IgM antibodies among lymphoma patients with anemia were (26%) , while (5%) in control group in case of IgG Abs seropositivity, The highest seropositivity of IgG antibodies among lymphoma patients with anemia were (30%), whereas (7%) in control group
The present study involved three types of lymphoma : Hodgkin lymphoma , Non- Hodgkin lymphoma and Burkitts lymphoma . All three types were diagnosed serologically in order to detect Anti-IgM antibodies
The result of Hodgkin lymphoma type showed that 10 out of a total 35 patients were positive result .In case of non-Hodgkin lymphoma , anti-human parvovirus IgM antibodies sero-positivity were 13 out of a total 56 sample.The result of third the type of lymphoma (Burkitts lymphoma) showed 3of a total 9 sample. In case of IgG antibodies detection, the result of Hodgkin lymphoma type showed that 11 out of a total 35 patients were positive result and in case of non-Hodgkin lymphoma , sero-positivity were 15 out of a total 56 sample . The results of the third type of lymphoma (Burkitts lymphoma) showed that positivity were 4 of a total 9 sample.
The study involved relation between degree of anemia and viral infection in lymphoma patients , sero-positivity to HPV-B19 IgM antibody showed that (20%) in patients with mild anemia, while (35%) in patients with severe anemia. The relation between Degree of anemia and HPV-B19 infection in lymphoma patients according to seropositivity to HPV-B19 IgG antibodies showed that 17 out of 60 patients with mild anemia, while 13 out of 40 in patients with severe anemia.
The present study included using of molecular technique for viral DNA detection, the findings in sample of lymphoma patients with anemia showed that (19%) gave DNA positive result . Control group only 3% sample gave positive result of parvovirus DNA
The first type of lymphoma ( Hodgkin lymphoma ) out of 35 sample there were only 7 sample give viral DNA positive result , The second group ( non-Hodgkin lymphoma ) The result reveal that 10 out of 56 sample with positive DNA result and the third types ( burikitts lymphoma ) that included only 9 sample as a total number , only 2 sample give positive result.
The anemia of present study was divided in to sub-group depending on the degree of anemia in lymphoma patient: the first sub group severs form , moderate anemia , and the second group severs from severe anemia. Both sub groups sample diagnosis by PCR technique in purpose to viral DNA detection . The results revealed that there were (11.66%) gave positive result for PCR technique in the first sub group ( mild , moderate anemia ),the other group ( severe anemia ) showed that (30%) gave positive result.
At the end it used multiple sequence alignment analysis of the partial NS1 protein gene sequence for local Human Parvovirus B19 isolates (N=8) with NCBI-Blast Human Parvovirus B19 NS1 protein gene . The results showed that multiple alignment analysis similarity (*)
The phylogenetic tree was constructed using Unweighted Pair Group method with Arithmetic Mean (UPGMA tree) in (MEGA 6.0 version) . The local Parvovirus B19 isolates showed closed related to NCBI-Blast Human Parvovirus
We studied frequency of B19 infection and its implications in lymphoma patients the aim of the present study was to highlight the association between anemia and B19 infection, and to assess the prevalence of parvovirusB19 infection in patients with lymphoma receiving chemotherapy.
keywords: Parvovirus B19 Infection, Anemia , Lymphoma patients , Chemotherapy
... These results indicate that norovirus VLPs are highly safe and effective in preventing viral infections [74,75]. Parvovirus B19 is a significant human pathogen that causes erythema infectiosum, also known as the fifth disease, a rash illness in children that can lead to arthral-gia syndrome in adults [76]. Meridian Life Science (Memphis, TN, USA), Inc. has expressed VP1 and VP2 proteins using the BEVS platform, assembled these two capsid proteins into VLPs, and designated the product VAI-VP705. ...
... After the second dose, most vaccinated individuals produced ELISA and neutralizing antibodies against Parvovirus B19. Currently, VAI-VP705 is in clinical phase I/II trials (NCT00379938) [76]. The Ebola virus (EBOV) is a zoonotic illness that can lead to severe hemorrhagic fever and high mortality rates [77]. ...
Vaccination is one of the most effective strategies to control epidemics. With the deepening of people’s awareness of vaccination, there is a high demand for vaccination. Hence, a flexible, rapid, and cost-effective vaccine platform is urgently needed. The baculovirus expression vector system (BEVS) has emerged as a promising technology for vaccine production due to its high safety, rapid production, flexible product design, and scalability. In this review, we introduced the development history of BEVS and the procedures for preparing recombinant protein vaccines using the BEVS platform and summarized the features and limitations of this platform. Furthermore, we highlighted the progress of the BEVS platform-related research, especially in the field of vaccine. Finally, we provided a new prospect for BEVS in future vaccine manufacturing, which may pave the way for future BEVS-derived vaccine development.
... VP1, as expected, can co-assemble with VP2 in vitro to produce VLPs. In vivo co-assembly of virions and VLPs containing both proteins has been described (Chandramouli et al., 2013;Gilbert et al., 2005;Leisi et al., 2013), thus the co-assemble in vitro just reflects the ability of the sequence shared between VP1 and VP2, the VP-region, to self-assemble into capsid-like structures (Bernstein et al., 2011;Brown et al., 1991;Wong et al., 1994). However, the correct folding and function of VP1u, or any other N-terminal fused protein, is independent of the folding of the VP-region (Cayetano-Cruz et al., 2018). ...
... A B19V candidate vaccine, based on VP1/VP2 VLPs produced in insect cells, has been tested in phase I clinical trial. However, the trial was stopped after some participants presented unexplained reactions (Bernstein et al., 2011). It was argued that the PLA2 activity of VP1u may be responsible for these reactions by releasing arachidonic acid and precursors of inflammatory mediators. ...
Virus-like particles (VLPs) from Parvovirus B19 (B19V) can be obtained by the self-assembly of the structural proteins VP1 and VP2. It is possible to produce B19V VLPs either from VP2 or a mixture of VP1 and VP2, through its heterologous expression in eukaryotic cells. The difference between VP1 and VP2 protein is a tract of 227 residues located at the N-terminal region of VP1, known as the VP1 unique region (VP1u). This region is critical for B19V infection, including tropism, cell internalization, and lysosomal scape through its phospholipase 2A activity. Herein, we report the in vitro self-assembly of VP1 to form VLPs. These species have phospholipase activity, suggesting that the phospholipase domain is correctly folded. Furthermore, VP1 and VP2 were co-assembled to produce hybrid VLPs which were able to bind and internalize in the non-permissive HepG2 cells, another evidence of the functionality of the in vitro refolded VP1u.
... To date, there is no vaccine for parvovirus B19 released for use in humans, although vaccine trials are being carried out [59][60][61][62]. An in vivo study was discontinued after the second dose of vaccination due to adverse skin reactions in some patients. ...
Parvovirus B19, a member of the Parvoviridae family, is a human pathogenic virus. It can be transmitted by respiratory secretions, hand-to-mouth contact, blood transfusion, or transplacental transmission. Most patients are asymptomatic or present with mild symptoms such as erythema infectiosum, especially in children. In rare cases, moderate-to-severe symptoms may occur, affecting blood cells and other systems, resulting in anemia, thrombocytopenia, and neutropenia. Non-immune pregnant women are at risk for fetal infection by parvovirus B19, with greater complications if transmission occurs in the first or second trimester. Infected fetuses may not show any abnormalities in most cases, but in more severe cases, there may be severe fetal anemia, hydrops, and even pregnancy loss. Maternal diagnosis of intrauterine parvovirus B19 infection includes IgG and IgM antibody testing. For fetal diagnosis, PCR is performed through amniocentesis. In addition to diagnosing the infection, it is important to monitor the peak of systolic velocity of the middle cerebral artery (PVS-MCA) Doppler to assess the presence of fetal anemia. There is no vaccine for parvovirus B19, and fetal management focuses on detecting moderate/severe anemia by fetal PVS-MCA Doppler, which, if diagnosed, should be treated with intrauterine transfusion by cordocentesis. Prevention focuses on reducing exposure in high-risk populations, particularly pregnant women.
... Finally, for women of generative age (14-45 years old), we considered their referral diagnosis and divided them into two categories: pregnant and non-pregnant women, in order to explore the differences in their serological status. Results from women of generative age were also analyzed based on their age category (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), and 36-45 years old). ...
This study aimed to estimate the serological status and dynamic changes in the prevalence of Parvovirus B19 (PVB19) antibodies within the general population residing in the northern part of the Republic of Serbia (Province of Vojvodina) during a 16-year period. Serum samples were analyzed for Human PVB19-specific IgM and IgG antibodies using enzyme-linked immunosorbent assay (ELISA). Throughout the study period, the overall seroprevalence was 49.51%. Approximately 10% of patients exhibited a serologic profile positive for PVB19 IgM antibodies. Notably, seroprevalence varied significantly, ranging from 9.12% in the pediatric cohort (ages 1–4 years) to 65.50% in the adult demographic (40–59 years old). Seroprevalence was higher (51.88%) among women compared to men (42.50%). Immunologically naive pregnant women in the age groups 26–36 and 36–45 years had 45% (OR = 0.55, 95% CI: 0.31–1.00) and 52% (OR = 0.48; 95% CI: 0.24–0.94) lower odds of having negative IgM and IgG compared to those in age group 16–25 years old. Improved knowledge of the epidemiology of PVB19 may assist clinicians in the differential diagnosis of PVB19 clinical manifestations. The PVB19 detection is particularly important for monitoring individuals in risk groups such as women of reproductive age, medical staff, patients with hematological disorders, and those with immunodeficiency.
... All volunteers in this trial developed neutralizing antibodies that lasted at least one year, suggesting that this vaccine was safe and immunogenic. However, when this study was moved to a larger cohort of volunteers, three cutaneous manifestations appeared and the study was halted [71]. The authors argue that the PLA2 activity of the VP1u of VP1 may be responsible for such reactogenicity, as it could release precursors of potent inflammatory mediators. ...
Virus-like particles (VLPs) comprise one or many structural components of virions, except their genetic material. Thus, VLPs keep their structural properties of cellular recognition while being non-infectious. VLPs of Parvovirus B19 (B19V) can be produced by the heterologous expression of their structural proteins VP1 and VP2 in bacteria. These proteins are purified under denaturing conditions, refolded, and assembled into VLPs. Moreover, chimeric forms of VP2 have been constructed to harbor peptides or functional proteins on the surface of the particles without dropping their competence to form VLPs, serving as presenting nanoparticles. The in-vitro assembly approach offers exciting possibilities for the composition of VLPs, as more than one chimeric form of VP2 can be included in the assembly stage, producing multifunctional VLPs. Here, the heterologous expression and in-vitro assembly of B19V structural proteins and their chimeras are reviewed. Considerations for the engineering of the structural proteins of B19V are also discussed. Finally, the construction of multifunctional VLPs and their future potential as innovative medical tools are examined.
... There are reports of the use of recombinant antiparvoviral vaccines with the development of neutralizing antibodies, however consistent results are still awaited and prospects of a more effective vaccine remain. 29 ...
Parvovirus B19 is a small nonenveloped single‐stranded DNA virus belonging to the parvoviridae family. The dermatological manifestations are varied ranging from infective to inflammatory, but the most common among infective etiologies is erythema infectiosum, also known as the fifth disease or ‘slapped cheek’ disease, which is mildly contagious. Clinical corroboration of symptoms and signs with serum antibody levels has been seen in acute and persistent parvoviral infections. Other dermatological manifestations of parvovirus B19 infections include erythema multiforme, vasculitis, reticular erythema, maculopapular eruptions, pustular eruptions, papular‐purpuric gloves and socks syndrome (PPGSS) and Gianotti‐Crosti syndrome. Skin lesions are quite characteristic and begin with oedema and erythema symmetrically localized to the hands and feet. Subsequently, petechial and purpuric changes appear varying from a few millimetres in diameter to larger, confluent patches. The primary target of parvovirus B19 is the hematopoietic‐erythroid cell line, specifically near the pronormoblast stage and the vulnerability to cellular damage increases along the differentiation lineage. There's multimodal clinical phenotypic presentation seen in parvoviral infections. Among the clinical expression of HPV B19 infections, the most common is dermatologic, however other manifestations such as rheumatologic and hematologic are not uncommon. However, some infections can be asymptomatic, especially in immunocompetent hosts, whereas in others with haematological abnormalities, these can lead to aplastic cellular crises.
... To date, there is no vaccine available for B19, as well as no structural characterization of B19 epitopes [77]. Some parvovirus B19 virus-like candidate vaccines have been developed and shown to be immunogenic in mice [78][79][80], which should be evaluated for their safety and effectiveness in humans through clinical trials. ...
An increasing number of reports have described human parvovirus B19 infection in association with a variety of neurological manifestations, especially in children. This study assessed the clinical and laboratory outcomes found in a case series of immunocompetent children who tested positive for parvovirus B19 by qualitative polymerase chain reaction assays of cerebrospinal fluid, in a tertiary referral center in the western Brazilian Amazon. We screened 178 children with clinically diagnosed central nervous system infections (meningoencephalitis). Of these, five (2.8%) were positive for parvovirus B19. A literature review also presented herein identified a further 50 cases of parvovirus B19 with neurological manifestations. Thus, even if the classic signs of parvovirus B19 infection are absent, such as the well-known rash, children with signs of neurological infection should also be evaluated for parvovirus B19 infection.
... Furthermore, in the clinical trial of the B19V vaccine, the volunteers who received a virus-like particle vaccine possessing PLA2 activity experienced immediate hypersensitivity in the site of the injection. This reaction was linked to the PLA2 activity of the VP1u [52]. Therefore, the PLA2 activity of VP1u could be at least partially responsible for the induction of stress signaling pathways in EC in vitro, and could also be relevant to the pathomechanism of B19V-associated endothelial damage in clinical settings. ...
Parvovirus B19 (B19V) is a widespread human pathogen possessing a high tropism for erythroid precursor cells. However, the persistence or active replication of B19V in endothelial cells (EC) has been detected in diverse human pathologies. The VP1 unique region (VP1u) of the viral capsid has been reported to act as a major determinant of viral tropism for erythroid precursor cells. Nevertheless, the interaction of VP1u with EC has not been studied. We demonstrate that recombinant VP1u is efficiently internalized by rats' pulmonary trunk blood vessel-derived EC in vitro compared to the human umbilical vein EC line. The exposure to VP1u was not acutely cytotoxic to either human- or rat-derived ECs, but led to the upregulation of cellular stress signaling-related pathways. Our data suggest that high levels of circulating B19V during acute infection can cause endothelial damage, even without active replication or direct internalization into the cells.
... Immunization experiments with vaccine candidates based on virus-like particles (VLPs) demonstrated that VP1u is essential to raise a strong neutralizing response against B19V [75,76]. However, the neutralization mechanism of antibodies targeting VP1u has remained largely elusive. ...
The viral protein 1 unique region (VP1u) of human parvovirus B19 (B19V) is a multifunctional capsid protein with essential roles in virus tropism, uptake, and subcellular trafficking. These functions reside on hidden protein domains, which become accessible upon interaction with cell membrane receptors. A receptor-binding domain (RBD) in VP1u is responsible for the specific targeting and uptake of the virus exclusively into cells of the erythroid lineage in the bone marrow. A phospholipase A2 domain promotes the endosomal escape of the incoming virus. The VP1u is also the immunodominant region of the capsid as it is the target of neutralizing antibodies. For all these reasons, the VP1u has raised great interest in antiviral research and vaccinology. Besides the essential functions in B19V infection, the remarkable erythroid specificity of the VP1u makes it a unique erythroid cell surface biomarker. Moreover, the demonstrated capacity of the VP1u to deliver diverse cargo specifically to cells around the proerythroblast differentiation stage, including erythroleukemic cells, offers novel therapeutic opportunities for erythroid-specific drug delivery. In this review, we focus on the multifunctional role of the VP1u in B19V infection and explore its potential in diagnostics and erythroid-specific therapeutics.
... In addition, clinical conditions linked to B19 infection include epilepsy, autoimmune hepatitis, myocarditis, and meningitis (17,68,101). There is currently no vaccines available to protect against infection, although attempts have been made to use virus-like particles for this purpose (12,14,62). ...
The parvoviruses are small nonenveloped single stranded DNA viruses that constitute members that range from apathogenic to pathogenic in humans and animals. The infection with a parvovirus results in the generation of antibodies against the viral capsid by the host immune system to eliminate the virus and to prevent re-infection. For members currently either being developed as delivery vectors for gene therapy applications or as oncolytic biologics for tumor therapy, efforts are aimed at combating the detrimental effects of pre-existing or post-treatment antibodies that can eliminate therapeutic benefits. Therefore, understanding antigenic epitopes of parvoviruses can provide crucial information for the development of vaccination applications and engineering novel capsids able to escape antibody recognition. This review aims to capture the information for the binding regions of ∼30 capsid-antibody complex structures of different parvovirus capsids determined to date by cryo-electron microscopy and three-dimensional image reconstruction. The comparison of all complex structures revealed the conservation of antigenic regions among parvoviruses from different genera despite low sequence identity and indicates that the available data can be used across the family for vaccine development and capsid engineering.
... The gap in the development of antiviral strategies and in particular the availability of antiviral drugs directed against B19V as compared to other viruses is striking [51]. A vaccine against B19V is an attainable goal, technically feasible, composed of VLPs produced in heterologous expression systems, and following progressive development [52][53][54] now shows promising characteristics in terms of immunogenicity and absence of reactogenicity [55,56]. However, because of the lack of relevant animal models, it is still at the very beginning of clinical evaluation, and its implementation is not included among the WHO priorities. ...
Parvovirus B19 (B19V) is a human pathogenic virus, responsible for an ample range of clinical manifestations. Infections are usually mild, self-limiting, and controlled by the development of a specific immune response, but in many cases clinical situations can be more complex and require therapy. Presently available treatments are only supportive, symptomatic, or unspecific, such as administration of intravenous immunoglobulins, and often of limited efficacy. The development of antiviral strategies against B19V should be considered of highest relevance for increasing the available options for more specific and effective therapeutic treatments. This field of research has been explored in recent years, registering some achievements as well as interesting future perspectives. In addition to immunoglobulins, some compounds have been shown to possess inhibitory activity against B19V. Hydroxyurea is an antiproliferative drug used in the treatment of sickle-cell disease that also possesses inhibitory activity against B19V. The nucleotide analogues Cidofovir and its lipid conjugate Brincidofovir are broad-range antivirals mostly active against dsDNA viruses, which showed an antiviral activity also against B19V. Newly synthesized coumarin derivatives offer possibilities for the development of molecules with antiviral activity. Identification of some flavonoid molecules, with direct inhibitory activity against the viral non-structural (NS) protein, indicates a possible line of development for direct antiviral agents. Continuing research in the field, leading to better knowledge of the viral lifecycle and a precise understanding of virus–cell interactions, will offer novel opportunities for developing more efficient, targeted antiviral agents, which can be translated into available therapeutic options.
... La María Hospital, Medellín -Colombia Argentine Catholic University Santa Maria de los Buenos Aires P arvovirus B19 is a global infection that can cause serious and life threatening disorders in susceptible patient groups. [1] Viruses of the family Parvoviridae, are among the smallest viruses described. The first pathogenic human parvovirus was discovered and named B19 from the coding of a serum sample, number 19 in panel B, that gave anomalous results during testing for hepatitis B. [2]. ...
Parvovirus B19 is a global infection that can cause serious and life threatening disorders in susceptible patient groups.
We present the clinical and epidemiological description of cases of aplasia of the red series without affecting
hematimetric indices in HIV positive patients with positive serology to Parvovirus B19 admitted to hospitalization between
April 2016 to April 2017.
... Si bien se han desarrollado vacunas recombinantes para PVB19 con producción de anticuerpos neutralizantes 110 , uno de los ensayos clínicos más recientes fue interrumpido por el desarrollo de exantemas 111 . ...
Parvovirus B19 is a community DNA virus with worldwide distribution with up to 85% seroprevalence in the elderly. There is a wide spectrum of clinical manifestations in parvovirus B19 infection of which cutaneous involvement is the most frequent one. Although most of these are self-limiting conditions, there are numerous syndromes and autoimmune diseases in which parvovirus B19 is postulated as a triggering factor, given its ability to induce the production of various autoantibodies and promote the presentation of autoantigens to T cells. This review describes the spectrum of cutaneous manifestations of parvovirus B19 infection and the evidence supporting its association with each of them. We propose a new classification of different diseases with cutaneous manifestations linked to parvovirus B19, based on the amount and quality of available evidence in the literature.
... Two vaccines developed based on VP1 and VP2 capsid proteins were immunogenic in phase 1 trials. However, the immunized persons suffered from headache, fever, gastrointestinal distress and fatigue (Ballou et al., 2003) in the first one and skin manifestations in the second (Bernstein et al., 2011). A new vaccine based on a saccharomyces cerevisiae-derived PVB19 virus-like-particle includes a point mutation in VP1 that eliminated its phospholipase A2 activity, a potential cause of the adverse reactions observed in the clinical trials. ...
Mechanism of atorvastatin hypolipidemic effect, side effects
... Two vaccines developed based on VP1 and VP2 capsid proteins were immunogenic in phase 1 trials. However, the immunized persons suffered from headache, fever, gastrointestinal distress and fatigue (Ballou et al., 2003) in the first one and skin manifestations in the second (Bernstein et al., 2011). A new vaccine based on a saccharomyces cerevisiae-derived PVB19 virus-like-particle includes a point mutation in VP1 that eliminated its phospholipase A2 activity, a potential cause of the adverse reactions observed in the clinical trials. ...
Understanding the perceptions of climate change impacts on people’s health and well-being in coastal communities is essential to develop adaptation strategies that will improve the health and well-being of community members in coastal areas. Here, an integrated mixed method approach: concurrent convergence parallel triangulation design - was used in 5 coastal communities in Tongatapu, Tonga. Community members were interviewed. Some of them had their health and well-being affected by climate change and some were not affected. Their responses were analyzed using a non-parametric test - chi-square analysis. Themes regarding the impact of climate change on health and well-being were then used to generate a further hypothesis. The results show that those whose health and well-being was affected differed significantly from those who were unaffected. They also indicated that all aspects of well-being: physical, mental and spiritual were affected by climate change and that people were eager to see the implementation of climate change adaptation strategies to improve their health and restore their mental well-being. It is thus essential to include these issues in adaptation strategies to ensure that local people are supporting and taking ownership of their resilience building.
... Da bi se izognili obolevnosti in umrljivosti plodov zaradi okužbe z B19V je naprimernejše preprečevati okužbo pri nosečnici. Cepivo proti B19V še ni razvito in ni na voljo za klinično uporabo (54). Zato so potrebni drugi preventivni ukrepi, kot je ozaveščanje žensk v reproduktivnem obdobju in zdravstvenih delavcev o tveganjih sveže okužbe v nosečnosti. ...
Parvovirus B19 (B19V) causes a mild disease called erythema infectiosum, also known as the fifh disease that affects mostly children and young adults. The virus can be transferred to the fetus during pregnancy in 31 to 51 % of the cases and can cause severe anaemia, non-immune hydrops fetalis or fetal death due to inhibition of erythropoiesis. It also affects the heart muscle, central nervous system, bones, and most likely can cause a subsequent arrest in children’s neurological development. It is estimated that 25–45 % of pregnant women are seronegative with a high risk of infection during pregnancy. A B19V infection in pregnant women is determined by detecting specific IgM and IgG antibodies, and in case of doubt, by using PCR method to detect viral DNA. Fetal infection with B19V is confirmed by detecting viral DNA in the amniotic fluid. In the case of either a suspected or confirmed fetal infection we monitor the fetus by ultrasound screening in a tertiary centre. We treat the fetus with an intrauterine transfusion at the first signs of anaemia or hydrops. To prevent fresh infections with B19V during pregnancy we should raise awareness amongst women and healthcare workers about the risks it poses for the fetus. The recommendations for management of women who are exposed to, are at risk of developing, or have developed B19V infection in pregnancy are published in this article.
... Congenital viral infections can be influenced by immunity and vaccination programs. Unfortunately, no suitable vaccine is available against HPV B19 (7). After primary HPV B19 infection long life immunity is created. ...
... Such VLPs are immunogenic in the animal experimental model as well as in humans. Phase I studies on initial VLPs produced in the recombinant baculovirus system showed immunogenicity and relative safety in humans (4), while phase II studies showed a remarkable reactogenicity (8), that lead to termination of the trial. VLPs devoid of the VP1u-associated viral phospholipase activity and produced in a yeast system recently led to the development of an alternative, apparently efficient and safer vaccine candidate (24). ...
Parvovirus B19 is a human pathogenic virus, a ssDNA member of the family Parvoviridae, characterized by a selective tropism for erythroid progenitor cells (EPCs) in the bone marrow and an ample pathogenetic potential. The selective tropism for EPCs can be explained both in terms of receptor-mediated tropism and of an intracellular permissive environment conditioned by the cell differentiation and proliferation stage. Infection of EPCs is productive, induces apoptosis and leads to a temporary arrest of erythropoiesis, which can usually be manifest in cases of underlying erythropoietic disorders or immune system deficiencies. Endothelial cells constitute an additional diffuse target, whose infection is mediated by ADE phenomenon, but is normally nonproductive and mainly leading to inflammatory processes. The relevance of parvovirus as a cardiotropic virus is recently emerging, while its capability of intrauterine transmission and consequences on the fetus is known and should not be overlooked. To the purpose of diagnosis, a combination of molecular and immunological methods offers the best discrimination of active infectious processes, and an application of these methods especially in cases of atypical presentations should be encouraged. Ongoing research is directed towards the development of a vaccine and the discovery of antiviral drugs that may be useful in the prevention and treatment of parvovirus B19 infections.
Virus-like particles (VLPs) have gained a lot of interest within the past two decades. The use of VLP-based vaccines to protect against three infectious agents—hepatitis B virus, human papillo-mavirus, and hepatitis E virus—has been approved; they are very efficacious and offer long-lasting immune responses. Besides these, VLPs from other viral infectious agents (that infect humans, animals, plants, and bacteria) are under development. These VLPs, especially those from human and animal viruses, serve as stand-alone vaccines to protect against viruses from which the VLPs were derived. Additionally, VLPs, including those derived from plant and bacterial viruses, serve as platforms upon which to display foreign peptide antigens from other infectious agents or metabolic diseases such as cancer, i.e., they can be used to develop chimeric VLPs. The goal of chimeric VLPs is to enhance the immunogenicity of foreign peptides displayed on VLPs and not necessarily the platforms. This review provides a summary of VLP vaccines for human and veterinary use that have been approved and those that are under development. Furthermore, this review summarizes chimeric VLP vaccines that have been developed and tested in pre-clinical studies. Finally, the review concludes with a snapshot of the advantages of VLP-based vaccines such as hybrid/mosaic VLPs over conventional vaccine approaches such as live-attenuated and inactivated vaccines.
Viral infectious diseases threaten human health and global stability. Several vaccine platforms, such as DNA, mRNA, recombinant viral vectors, and virus-like particle-based vaccines have been developed to counter these viral infectious diseases. Virus-like particles (VLP) are considered real, present, licensed and successful vaccines against prevalent and emergent diseases due to their non-infectious nature, structural similarity with viruses, and high immunogenicity. However, only a few VLP-based vaccines have been commercialized, and the others are either in the clinical or preclinical phases. Notably, despite success in the preclinical phase, many vaccines are still struggling with small-scale fundamental research owing to technical difficulties. Successful production of VLP-based vaccines on a commercial scale requires a suitable platform and culture mode for large-scale production, optimization of transduction-related parameters, upstream and downstream processing, and monitoring of product quality at each step. In this review article, we focus on the advantages and disadvantages of various VLP-producing platforms, recent advances and technical challenges in VLP production, and the current status of VLP-based vaccine candidates at commercial, preclinical, and clinical levels.
The Baculovirus Expression Vector System (BEVS), a mature foreign protein expression platform, has been available for decades, and has been effectively used in vaccine production, gene therapy, and a host of other applications. To date, eleven BEVS-derived products have been approved for use, including four human vaccines [Cervarix against cervical cancer caused by human papillomavirus (HPV), Flublok and Flublok Quadrivalent against seasonal influenza, Nuvaxovid/Covovax against COVID-19], two human therapeutics [Provenge against prostate cancer and Glybera against hereditary lipoprotein lipase deficiency (LPLD)] and five veterinary vaccines (Porcilis Pesti, BAYOVAC CSF E2, Circumvent PCV, Ingelvac CircoFLEX and Porcilis PCV). The BEVS has many advantages, including high safety, ease of operation and adaptable for serum-free culture. It also produces properly folded proteins with correct post-translational modifications, and can accommodate multi-gene– or large gene insertions. However, there remain some challenges with this system, including unstable expression and reduced levels of protein glycosylation. As the demand for biotechnology increases, there has been a concomitant effort into optimizing yield, stability and protein glycosylation through genetic engineering and the manipulation of baculovirus vector and host cells. In this review, we summarize the strategies and technological advances of BEVS in recent years and explore how this will be used to inform the further development and application of this system.
Parvovirus B19 (B19) belongs to the Erythroparvovirus genus and is known to cause the fifth disease in children. Primary infection of pregnant women is associated with a high risk of hydrops fetalis and stillbirth due to severe fetal anemia. Virus-like particle (VLP) vaccine candidates for B19 have been developed, although none have been approved so far. The B19 phospholipase A2 domain (B19 PLA2), located in the VP1 unique region, is believed to be associated with adverse inflammatory reactions, and previous effective attempts to improve this vaccine modality inserted a mutation to impair the PLA2 activity of VLPs. In this study, we designed VLPs with a deletion mutant of PLA2 (⊿PLA2 B19 VLP), devoid of PLA2 activity, and confirmed their immunogenicity and safe use in vivo. These results were supported by the lack of histological inflammatory reactions at the site of immunization or the production of IL-6 in ⊿PLA2 B19 VLP-immunized mice, that were observed in mice immunized with B19 VLPs. CD4⁺ T cells from mice vaccinated with VLPs and B19-seropositive human samples were not activated by B19 PLA2 stimulation, suggesting that the B19 PLA2 domain does not constitute a major CD4⁺ T cell epitope. Most importantly, the ⊿PLA2 B19 VLPs induced neutralizing antibodies against B19, in levels similar to those found in B19-seropositive human samples, indicating that they could be used as a safe and effective vaccine candidate against B19.
Résumé
L’infection aiguë à Parvovirus B19 (PVB19), responsable du mégalérythème épidémique de l’enfant, entraîne chez l’adulte immunocompétent des polyarthralgies aspécifiques associées à des lésions cutanées et des manifestations plus rares (hépatiques, neurologiques, cardiaques ou néphrologiques). Chez l’immunodéprimé, les cytopénies sont plus fréquentes et dans certains cas la virémie persiste et est responsable d’une infection chronique à PVB19. Le PVB19 est également à l’origine de crises érythroblastopéniques au cours de maladies hémolytiques chroniques. L’infection aiguë à PVB19 est un diagnostic différentiel de certaines maladies auto-immunes et a été suspecté comme agent déclenchant de certaines pathologies auto-immunes du fait de sa capacité à favoriser l’émergence de marqueurs d’auto-immunité. Des mécanismes de mimétisme moléculaire, d’induction d’apoptose et d’activation de certaines enzymes ont été démontrés, expliquant en partie la production d’auto-anticorps au cours de l’infection. La démonstration d’une relation causale dans le déclenchement de maladie auto-immune reste cependant à réaliser. Cette mise au point propose une synthèse des données cliniques de l’infection à PVB19 chez l’adulte avec un focus particulier sur ces liens avec l’auto-immunité.
Parvovirus B19 is a small, non-enveloped, single-stranded DNA virus with global distribution. It is primarily known for being the causative agent of fifth disease, also known as erythema infectiosum, a common self-limiting childhood disease characterized by the development of a rash. During infection, it targets erythroid progenitor cells in bone marrow, where it replicates and ultimately induces cellular apoptosis. In the correct patient population, it may be responsible for the development of arthropathy, aplastic crisis, nonimmune hydrops fetalis, viral-associated hepatitis, and myocarditis. However, most infections are asymptomatic and remain undetected. Here, we review the nature of this virus to provide information about its biology; interactions with the human host; how those interactions shape the clinical presentation; and, finally, the available diagnostic approaches.
Infections by DNA viruses during pregnancy are associated with increased health risks to both mother and fetus. Although not all DNA viruses are related to an increased risk of complications during pregnancy, several can directly infect the fetus and/or cause placental dysfunction. During NIPT analysis, the presence of viral DNA can be detected, theoretically allowing screening early in pregnancy. Although treatment options are currently limited, this might rapidly change in the near future. It is therefore important to be aware of the potential impact of these viruses on feto‐maternal health. In this manuscript we provide a brief introduction into the most commonly detected DNA viruses in human cell‐free DNA sequencing experiments and their pathogenic potential during pregnancy. This article is protected by copyright. All rights reserved.
Background
Parvovirus B19 (B19) is a well-known cause of fifth disease in children, but infection during pregnancy may cause hydrops fetalis and stillbirth. The receptor-binding domain (RBD) of the VP1 unique capsid plays a pivotal role in infection. Here, we aimed to improve the immunogenicity of an RBD-based vaccine by genetically fusing it with Streptococcus pneumoniae surface protein A (PspA).
Methods
Mice were intramuscularly injected with RBD-based vaccines. Antigen-specific antibodies and neutralizing activity against B19 were measured. Protective immunity against S. pneumoniae was evaluated by monitoring the survival of mice nasally challenged with bacteria and determining antigen-specific T cell activation in splenic cells.
Results
RBD alone failed to generate neutralizing antibodies against B19, but fusion with PspA induced higher levels of neutralizing IgG compared to B19 virus-like particles. Furthermore, a comparable level of PspA-specific IgG was induced by RBD-PspA and PspA alone, which was sufficient to protect mice against pneumococcal infection. Stimulation with PspA, but not RBD, induced cytokine production in splenic cells from mice immunized with RBD-PspA, suggesting that PspA-specific T cells supported immunoglobulin class switching of both RBD- and PspA-specific B cells.
Conclusions
RBD-PspA should be an effective bivalent vaccine against B19 and S. pneumoniae infections.
Parvovirus B19 (B19V) is a widespread infection that may affect 1-5% of pregnant women, mainly with normal pregnancy outcome. Vertical transmission occurs in 33–51% of cases of maternal infection. B19V infection is an important cause of fetal morbidity (fetal anaemia and non-immune hydrops) and mortality, predominantly in the second trimester.
Diagnosis of B19V infection requires a multi-method approach using mainly serology and PCR techniques. Severe fetal anaemia is managed with intrauterine transfusion with perinatal survival rates following intrauterine transfusion ranging from 67% to 85%. If fetal anaemia is mild, and considering that hydrops can spontaneously resolve, invasive therapy is not recommended and B19V complicated pregnancy may be non-invasively monitored by serial ultrasound examination and MCV-PSV measurements. As an alternative, intrauterine IVIG therapy has been described with successful treatment of fetal hydrops.
No specific antiviral therapy or vaccine is presently available for B19V infection but efforts in the search for compounds inhibiting B19V replication are now being pursued. New virus-like-particle based parvovirus B19 vaccine candidates, produced by co-expressing VP2 and either wild-type VP1 or phospholipase-negative VP1 in a regulated ratio from a single plasmid in Saccharomyces cerevisiae have been developed and show sufficient promise to test in humans.
This review will outline the role of baculoviruses in gene therapy and future potential in personalized medicine. Baculoviruses are a safe, non-toxic, non-integrative vector with a large cloning capacity. Baculoviruses are also a highly adaptable, low-cost vector with a broad tissue and host tropism due to their ability to infect both quiescent and proliferating cells. Moreover, they only replicate in insect cells, not mammalian cells, improving their biosafety. The beneficial properties of baculoviruses make it an attractive option for gene delivery. The use of baculoviruses in gene therapy has advanced significantly, contributing to vaccine production, anti-cancer therapies and regenerative medicine. Currently, baculoviruses are primarily used for recombinant protein production and vaccines. This review will also discuss methods to optimize baculoviruses protein production and mammalian cell entry, limitations and potential for gene therapy and personalized medicine. Limitations such as transient gene expression, complement activation and virus fragility are discussed in details as they can be overcome through further genetic modifications and other methods. This review concludes that baculoviruses are an excllent candidate for gene therapy, personalized medicine and other biotherapeutic applications.
The family Parvoviridae comprises a large and diverse set of animal viruses, found in invertebrate and vertebrate hosts. Features are an ssDNA genome encapsidated in an icosahedral protein shell of about 20–28 nm, a diverse strategy to express genomes of small dimensions, and a strict dependence on the cell environment for productive infection. Within the family, viruses are found that can infect humans, with different characteristics related to epidemiology, virus-cell interactions and potential to cause diseases. Most relevant for its pathogenetic potential is Parvovirus B19, others include the human Bocaviruses, the Human Tetraparvovirus and novel Human Protoparvoviruses.
When an individual is exposed to a viral pathogen for the first time, the adaptive immune system is naive and cannot prevent virus replication. The consequence may be severe disease. At the same time, the host may rapidly generate a pathogen-specific immune response that will prevent disease if the virus is encountered again. Parvovirus B19 provides one such example. Children with sickle cell disease can experience life-threatening transient aplastic crisis when first exposed to parvovirus B19, but an effective immune response confers lifelong protection. We briefly examine the induction and benefits of virus-induced immunity. We focus on three human viruses for which there are no licensed vaccines (respiratory syncytial virus, human immunodeficiency virus type 1, and parvovirus B19) and consider how virus-induced immunity may inform successful vaccine design.
В статье представлены особенности течения парвовирусной инфекции у беременных. Описаны последствия поражения плода патогеном. Освещены возможности оценки риска врожденной парвовирусной инфекции, антенатальной диагностики, интерпретации результатов лабораторных и инструментальных методов исследования. Представлены подходы к лечению, обсуждены возможности профилактики заболевания.
У статті наведені сучасні дані про різні аспекти проблеми парвовірусної інфекції. На підставі аналізу даних літератури описані етіологія, епідеміологія, шляхи передачі інфекції, особливості патогенезу у дорослої людини й фетальної парвовірусної інфекції. Наведені клінічні прояви основних форм захворювання.
Parvovirus B19 was discovered in 1975, and the first reports associating B19 with human disease came 6 years later, when B19 was linked to cases of aplastic crisis in patients with sickle cell disease. Since then, B19 infection has become a recognized infectious complication in the immunocompromised host, including persons infected with human immunodeficiency virus (HIV), as well as solid organ (SOT) and hematopoietic cell transplant (HCT) recipients. While typically a benign, self-limited infection in immunocompetent hosts, B19 can have serious sequelae in the immunocompromised host. Fundamentals of disease pathogenesis, clinical manifestations, diagnosis, and treatment options are discussed.
Clinical manifestations of human parvovirus B19 infection can vary widely and may be atypical in solid organ transplant (SOT) recipients. However, disease is apparent when there is destruction of erythrocyte progenitor cells leading to severe acute or chronic anemia with lack of an appropriate reticulocyte response in the setting of active parvovirus B19 infection. Serology may not reliably establish the diagnosis. High‐level viremia is more likely to be associated with symptomatic disease. Conversely, ongoing DNAemia after infection may not be clinically significant, if detected at low levels. Despite lack of robust data, intravenous immunoglobulin (IVIG) is frequently used for the treatment of SOT recipients with symptomatic parvovirus B19 infection. Although the optimal dosage and duration of IVIG is not known, most patients receive a total of 2 g/kg over a period of 2‐5 days. A daily dose of 1 g/kg or more seems to be associated with higher incidence of toxicity. Application of standard and droplet isolation precautions remains the cornerstone for preventing human parvovirus B19 transmission. Additional research is needed to assess the efficacy of current and novel therapies and to develop a safe and effective parvovirus B19 vaccine.
Parvovirus B19 infections are typically mild in healthy individuals, but can be life threatening in individuals with sickle cell disease (SCD). A Saccharomyces cerevisiae-derived B19 VLP vaccine, now in pre-clinical development, is immunogenic in wild type mice when administered with the adjuvant MF59. Because SCD alters the immune response, we evaluated the efficacy of this vaccine in a mouse model for SCD. Vaccinated mice with SCD demonstrated similar binding and neutralizing antibody responses to those of heterozygous littermate controls following a prime-boost-boost regimen. Due to the lack of a mouse parvovirus B19 challenge model, we employed a natural mouse pathogen, Sendai virus, to evaluate SCD respiratory tract responses to infection. Normal mucosal and systemic antibody responses were observed in these mice. Results demonstrate that mice with SCD can respond to a VLP vaccine and to a respiratory virus challenge, encouraging rapid development of the B19 vaccine for patients with SCD.
Infections acquired in-utero or during the birth process are a significant cause of fetal and neonatal mortality and morbidity, sometimes effects being delayed into late childhood. The newborn infant with a congenital infection may be completely asymptomatic or demonstrate abnormal/restricted growth, poor weight gain, developmental delay, or multiple laboratory abnormalities. The “TORCH” acronym is well recognized in the field of neonatal/perinatal medicine. However, there are other well-described causes of in-utero infection, including varicella zoster virus, and parvovirus B19. The chapter will give a concise, yet informative, description of the most commonly observed congenital viral infections. Other congenital infections are beyond the scope of this title.
During acute Human parvovirus B19 (B19) infection a transient reduction in blood haemoglobin concentration is induced, due to a 5-7 day cessation of red cell production. This can precipitate severe anaemia in subjects with a range of pre-existing conditions. Of the disease markers that occur during B19 infection, high IgM levels occur closest in time to the maximum reduction in haemoglobin concentration. Previous studies of the contribution of B19 to severe anaemia among young children in Africa have yielded varied results. This retrospective case/control study seeks to ascertain the proportion of severe anaemia cases precipitated by B19 among young children admitted to a Kenyan district hospital.
Archival blood samples from 264 children under 6 years with severe anaemia admitted to a Kenyan District Hospital, between 1999 and 2004, and 264 matched controls, were tested for B19 IgM by Enzyme Immunosorbent Assay and 198 of these pairs were tested for B19 DNA by PCR. 536 samples were also tested for the presence of B19 IgG.
7 (2.7%) cases and 0 (0%) controls had high B19 IgM levels (Optical Density > 5 x cut-off value) (McNemar's exact test p = 0.01563), indicating a significant association with severe anaemia. The majority of strongly IgM positive cases occurred in 2003.10/264 (3.7%) cases compared to 5/264 (1.9%) controls tested positive for B19 IgM. This difference was not statistically significant, odds ratio (OR) = 2.00 (CI95 [0.62, 6.06], McNemar's exact test p = 0.3018. There was no significant difference between cases and controls in the B19 IgG (35 (14.8%) vs 32 (13.6%)), OR = 1.103 (CI95 [0.66, 1.89], McNemar's exact test, p = 0.7982), or the detection of the B19 DNA (6 (3.0%) vs 5 (2.5%)), OR = 1.2 (CI95 [0.33, 4.01], McNemar's exact test p = 1).
High B19 IgM levels were significantly associated with severe anaemia, being found only among the cases. This suggests that 7/264 (2.7%) of cases of severe anaemia in the population of children admitted to KDH were precipitated by B19. While this is a relatively small proportion, this has to be evaluated in the light of the IgG data that shows that less than 15% of children in the study were exposed to B19, a figure much lower than reported in other tropical areas.
Parvovirus B19 is the causative agent of erythema infectiosum. In addition, parvovirus B19 infection may be associated with
other disease manifestations, namely, thrombocytopenia or granulocytopenia, spontaneous abortion or hydrops fetalis in pregnant
women, acute and chronic arthritis, and systemic lupus erythematosus. Based on sequence homology data, a phospholipase A2
motif has been identified in the VP1 unique region of parvovirus B19. (Y. Li et al., J. Gen. Virol. 82:2821-2825, 2001; Z.
Zadori et al., Dev. Cell 1:291-302, 2001). We have established a new in vitro assay based on electrospray ionization tandem
mass spectroscopy to show that phospholipase A2 activity is present in the VP1 unique region produced in Escherichia coli and in virus-like particles consisting of combinations of VP1 and VP2 proteins expressed by recombinant baculovirus. The
enzyme activity of the VP1 unique region showed typical Ca2+ dependency and could be inhibited by manoalide and 4-bromophenacylbromide, which bind covalently to lysine and histidine
residues, respectively, as part of the active center of the enzyme. By using subfragments, we demonstrated an association
between the phospholipase A2-like activity and the carboxy-terminal domain of the VP1 unique region.
Severe anemia (hemoglobin level, <50 g/L) is a major cause of death among young children, and it arises from multiple factors, including malaria and iron deficiency. We sought to determine whether infection with parvovirus B19 (B19), which causes the cessation of erythropoiesis for 3-7 days, might precipitate some cases of severe anemia.
Archival blood samples collected in the Wosera District of Papua New Guinea, from 169 children 6 months-5 years old with severe anemia and from 169 control subjects matched for age, sex, and time were tested for B19 immunoglobulin M (IgM) by enzyme immunoassay and for B19 DNA by nested polymerase chain reaction (PCR). A total of 168 separate samples from children in the Wosera District were tested for B19 IgG.
A strong association between acute B19 infection (positive by both IgM and PCR) and severe anemia was found (adjusted odds ratio, 5.61 [95% confidence interval, 1.93-16.3]). The prevalence of parvovirus B19 IgG reached >90% in 6-year-olds.
B19 infections play a significant role in the etiology of severe anemia in this area of malarial endemicity. Given the high levels of morbidity and mortality associated with severe anemia in such regions, the prevention of B19 infection with a vaccine might be a highly effective public health intervention.
We conducted a seroprevalence survey in Belgium, Finland, England & Wales, Italy and Poland on 13 449 serum samples broadly representative in terms of geography and age. Samples were tested for the presence of immunoglobulin G antibody using an enzyme immunoassay. The age-specific risk of infection was estimated using parametric and non-parametric statistical modelling. The age-specific risk in all five countries was highest in children aged 7-9 years and lower in adults. The average proportion of women of child-bearing age susceptible to parvovirus B19 infection and the risk of a pregnant women acquiring B19 infection during pregnancy was estimated to be 26% and 0.61% in Belgium, 38% and 0.69% in England & Wales, 43.5% and 1.24% in Finland, 39.9% and 0.92% in Italy and 36.8% and 1.58% in Poland, respectively. Our study indicates substantial epidemiological differences in Europe regarding parvovirus B19 infection.
Approximately 70 years passed between the licensing of alum salts as vaccine adjuvants and that of MF59™ MF59, an oil-in-water emulsion, is currently licensed for use in the elderly as an adjuvant in seasonal influenza vaccines. Its mechanism of action is not fully understood, but enhancement of the interaction between the antigen and the dendritic cell seems to be involved. When used with seasonal influenza vaccines, an increase occurs in the hemagglutination inhibition antibody titers against some, but not all, seasonal vaccine influenza strains. The adjuvant effect is more pronounced when MF59 is combined with novel influenza antigens such as H9 and H5. The use of the adjuvant is associated with an increase in the frequency of local and systemic early post-vaccine adverse events (3-7 days), but no increase in adverse events was observed thereafter. Currently, MF59 is under evaluation as an adjuvant with other antigens such as pandemic influenza antigens and cytomegalovirus antigens.
Detection of viral genome in rejecting cardiac transplant patients has been reported, with coxsackievirus and adenovirus causing premature graft failure. Recently, parvovirus B19 (PVB19) genome in myocardial samples has been increasingly reported, but its role in cardiac pathology and effect on transplant graft survival are unknown. The objectives of this study were to determine if changes in the viruses identified in the myocardium represent an epidemiologic shift in viral myocardial disease and whether PVB19 adversely affects transplant graft survival.
From September 2002 to December 2005, nested polymerase chain reaction was used to evaluate endomyocardial biopsy specimens for 99 children (aged 3 weeks-18 years) with heart transplants for the presence of viral genome. Cellular rejection was assessed by histology of specimens. Transplant coronary artery disease (TCAD) was diagnosed by coronary angiography or histopathology.
Specimens from 700 biopsies were evaluated from 99 patients; 121 specimens had viral genome, with 100 (82.6%) positive for PVB19, 24 for Epstein-Barr virus (EBV; 7 positive for PVB19 and EBV), 3 for CMV, and 1 for adenovirus. Presence of PVB19 genome did not correlate with rejection score, nor did a higher viral copy number. Early development of advanced TCAD (p < 0.001) occurred in 20 children with persistent PVB19 infection (> 6 months).
PVB19 is currently the predominant virus detected in heart transplant surveillance biopsy specimens, possibly representing an epidemiologic shift. Cellular rejection does not correlate with the presence or quantity of PVB19 genome in the myocardium, but children with chronic PVB19 infection have increased risk for earlier TCAD, supporting the hypothesis that PVB19 negatively affects graft survival.
To the Editor: Viral and postviral myocarditis are the major causes of acute and chronic dilated cardiomyopathy.1 To gain insight into the pathogenesis of parvovirus B19–associated myocarditis as an endothelial-cell–mediated disease (Figure 1A), we measured viral loads in endomyocardial biopsy specimens obtained from 498 patients (341 men and 157 women; mean [±SD] age, 46.93±15.85 years) with myocarditis2 or chronic dilated cardiomyopathy who were positive for parvovirus B19 on immunohistologic analysis. A total of 91 noninflamed normal hearts obtained from autopsies served as controls. We found that parvovirus B19 genomes were significantly more likely to be detected in the endomyocardial biopsy . . .
FluBlok, a recombinant trivalent hemagglutinin (HA) vaccine produced in insect cell culture using the baculovirus expression system, provides an attractive alternative to the current egg-based trivalent inactivated influenza vaccine (TIV) manufacturing process. FluBlok contains three times more HA than TIV and does not contain egg-protein or preservatives. This review discusses the four main clinical studies that were used to support licensure of FluBlok under the 'Accelerated Approval' mechanism in the United States.
B19 parvovirus is pathogenic in humans, causing fifth disease, transient aplastic crisis, some cases of hydrops fetalis, and acquired pure red cell aplasia. Efforts to develop serologic assays and vaccine development have been hampered by the virus's extreme tropism for human bone marrow and the absence of a convenient culture system. We constructed recombinants containing either the major (VP2) or minor (VP1) structural proteins of B19 in a baculovirus-based plasmid, from which the polyhedrin gene had been deleted; these recombinant plasmids were used to generate recombinant infectious baculovirus. Subsequent infection of insect cells in vitro resulted in high-level expression of either B19VP1 or VP2. Parvovirus capsids were obtained by self-assembly in cell cultures coinfected with either VP1- and VP2-containing baculoviruses or, surprisingly, VP2-containing baculoviruses alone. Empty B19 capsids composed of VP1 and VP2 could replace serum virus as a source of antigen in a conventional immunoassay for detection of either IgG or IgM antiparvovirus antibodies in human serum. Immunization of rabbits with capsids composed of VP1 and VP2 resulted in production of antisera that recognized serum parvovirus on immunoblot and neutralized parvovirus infectivity for human erythroid progenitor cells. Baculovirus-derived parvovirus antigen can substitute for scarce viral antigen in immunoassays and should be suitable as a human vaccine.
Phospholipase A2 is the major allergen in honeybee venom. Recombinant phospholipase A2 was produced in prokaryotes and tested for its biologic activity by intracutaneous skin testing with serial 10-fold dilutions in comparison with native and deglycosylated phospholipase A2 in patients allergic to bee venom. Linear regressions of the log of the wheal area versus the log of the allergen concentration were calculated for all allergens in each patient. The relative allergenic potency of the various preparations was analyzed by comparing the linear regressions. Native phospholipase A2 was about 10 times more potent than whole bee venom. None of 58 patients allergic to bee venom was missed by testing with native phospholipase A2 alone. This allergen and deglycosylated native phospholipase A2 resulted in similar skin reactions, indicating that the sugar residues were of little relevance for IgE-binding in the patients tested. Native phospholipase A2 also had relative potency similar to that of recombinant refolded phospholipase A2, whereas recombinant nonrefolded phospholipase A2 had almost no biologic activity in skin testing. These results demonstrate in vivo activity of the recombinant bee venom allergen phospholipase A2. Although correct refolding is a prerequisite for type I skin reactivity, glycosylation seems to be less important.
We studied the epidemiology of human parvovirus B19 infection in 308 children with homozygous sickle cell (SS) disease and 239 controls with a normal haemoglobin (AA) genotype followed from birth in a cohort study. Annual serum samples identified the time and frequency of B19 infection, which did not differ between SS and AA children, about 40% of each group developing specific IgG by age 15. B19 infection followed an epidemic pattern similar to that observed for aplastic crises; accounted for all 91 aplastic crises that occurred; and was found in an additional 23 SS patients, of whom 10 showed mild haematological changes and 13 no changes. The magnitude or duration of IgG response did not differ between these groups. No patient had 2 attacks of aplasia and no patient nor control had 2 attacks of B19 infection. Following B19 infection, serial specific IgG concentrations remained high after 5 years in only 45% of SS patients, although the rarity of recurrent aplasia suggests lifelong immunity. B19 infection accounts for most if not all aplastic crises in SS disease, but at least 20% of infections do not result in aplasia. An effective vaccine against B19 might make an important contribution to the management of sickle cell disease.
Recombinant baculoviruses were used to produce human B19 parvovirus empty capsids composed of only VP2 and VP2 capsids containing
4%,25%,35%, or 41% VP1 protein. Immunogenicity of the purified capsids, formulated with or without adjuvant, was evaluated
in mice, guinea pigs, and rabbits. Sera were analyzed for total anti-B19 parvovirus antibodies, antibodies specific to the
region unique to the VP1 capsid protein, and virus neutralizing antibodies. A relationship was observed between the development
of antibodies specific to sequences unique to the VPl protein and virus neutralization. The polypeptide composition of the
empty capsid immunogens appeared to be important for elicitation ofpotent virus neutralizing activity. VP2 capsid immunogens
devoid of VP1 protein, or consisting of only 4% VP1, the composition of naturally occurring virions, were generally poor at
eliciting high levels of virus neutralizing activity. Capsids consisting of ⩾25% VP1 protein efficiently and consistently
provoked vigorous B19 virus neutralizing responses. Recombinant empty capsids enriched for the VPl protein should serve as
the basis for a human B19 parvovirus vaccine.
Hyaluronidase (Hya) is one of several allergens in honeybee venom. Its cDNA sequence was recently described.
We sought to express recombinant Hya in prokaryotic and eukaryotic systems and to compare it with natural (n)Hya for biologic activity.
In Escherichia coli Hya was produced as inclusion body 6 x His-fusion protein. In baculovirus-infected insect cells expression was obtained by cotransfection of linearized Bac-N-Blue DNA and pMelBac transfer vector into Spodoptera frugiperda cells.
Enzymatic activity of Hya from the baculovirus system was equal to nHya, and that of the enzyme expressed in E. coli was only 20% to 30% of nHya. In vitro IgE binding was similar in nHya and the enzyme from baculovirus but markedly lower in Hya expressed in E. coli.
Biologic activity of Hya expressed in baculovirus-infected insect cells was comparable with that of the natural enzyme, indicating a native-like conformation of the recombinant protein. In contrast, the enzyme expressed in E. coli as an inclusion-body protein and reconstituted in vitro reached only 20% to 30% of the activity of nHya.
The lipid mediators generated by phospholipases A(2) (PLA(2)), free arachidonic acid (AA), eicosanoids, and platelet-activating factor, modulate neuronal activity; when overproduced, some of them become potent neurotoxins. We have shown, using primary cortical neuron cultures, that glutamate and secretory PLA(2) (sPLA(2)) from bee venom (bv sPLA(2)) and Taipan snake venom (OS2) elicit synergy in inducing neuronal cell death. Low concentrations of sPLA(2) are selective ligands of cell-surface sPLA(2) receptors. We investigated which neuronal arachidonoyl phospholipids are targeted by glutamate-activated cytosolic calcium-dependent PLA(2) (cPLA(2)) and by sPLA(2). Treatment of (3)H-AA-labeled cortical neurons with mildly toxic concentrations of sPLA(2) (25 ng/ml, 1.78 nM) for 45 min resulted in a two- to threefold higher loss of (3)H-AA from phosphatidylcholine (PC) than from phosphatidylethanolamine (PE) and in minor changes in other phospholipids. A similar profile, although of greater magnitude, was observed 20 hr posttreatment. Glutamate (80 microM) induced much less mobilization of (3)H-AA than did sPLA(2) and resulted in a threefold greater degradation of (3)H-AA PE than of (3)H-AA PC by 20 hr posttreatment. Combining sPLA(2) and glutamate resulted in a greater degradation of PC and PE, and the N-methyl-D-aspartate receptor antagonist MK-801 only blocked glutamate effects. Thus, activation of the arachidonate cascade induced by glutamate and sPLA(2) under experimental conditions that lead to neuronal cell death involves the hydrolysis of different (perhaps partially overlapping) cellular phospholipid pools.
The clinical and pathomorphological patterns of parvovirus B19 (PVB19)-associated diseases is the result of a balance between virus, host target cells and immune response. It is a characteristic feature of PVB19 that in patients with various other preexisting diseases, e.g., many hemolytic anemias, immune complex-mediated vasculitic disorders, and primary or secondary immunodeficiencies, the underlying diseases can be triggered, aggravated or complicated by severe organ manifestations. Identification of PVB19 by means of routine histology and immunohistology is only given in lytic infections occurring in transient aplastic anemia or nonimmune hydrops fetalis by the detection of viral inclusion bodies in erythroid precursor cells. In all other PVB19-associated diseases, molecular pathological methods must be applied. In this report, quantitative real-time polymerase chain reaction was used to determine the viral load in formalin-fixed and paraffin-embedded tissues derived from various organs. Using in situ hybridization it was demonstrated that endothelial cells of the microcirculatory periphery of the heart and hepatobiliar system in lytic infections are PVB19-specific target cells in children and adults. Because treatment of lytic PVB19 infection has been successfully applied, the pathologist should be alerted to include PVB19 into the diagnostic spectrum of viral disease, especially in immunocompromised patients.
A recombinant human parvovirus B19 vaccine (MEDI-491; MedImmune) composed of the VP1 and VP2 capsid proteins and formulated
with MF59C.1 adjuvant was evaluated in a randomized, double-blind, phase 1 trial. Parvovirus B19–seronegative adults (n=24)
received either 2.5 or 25 μg MEDI-491 at 0, 1, and 6 months. MEDI-491 was safe and immunogenic. All volunteers developed neutralizing
antibody titers that peaked after the third immunization and were sustained through study day 364
Parvovirus B19, the only known pathogenic human parvovirus is the aetiologic agent of erythema infectiosum, transient aplastic crisis, pure red cell aplasia, and hydrops fetalis. Transmission is either by respiratory secretions or, as it can be present at high titre in plasma, by blood and blood products. B19 is only cultured with difficulty in vitro, and there is no readily available assay for detecting B19 infectivity or neutralizing antibodies.
In this study, we evaluated different methods to detect viral infection for the purpose of developing automated methods for large-scale testing of viral infectivity, development of neutralizing antibody and viral inactivation assays.
Different cell lines were evaluated for their ability to support B19 infection and assays tested for sensitivity and ease of performing. A high-throughput assay was validated by determining infectious virus in blood pools and for determining neutralizing antibody in sera.
B19 protein production was detected by immunofluorescence (IF) staining and increased viral DNA production by dot blot hybridization and quantitative PCR. The detection of RNA transcripts by RT-PCR assay and quantitative RT-PCR (qRT-PCR) was used as an indirect marker for infection. Of the cell lines tested, the subclone UT7/Epo-S1 showed the greatest sensitivity to B19 infection, with detection of viral transcripts by qRT-PCR the preferred assay. The assays were validated by experiments to determine the infectious titre of sera from acutely infected humans, to evaluate the presence of infectious virus in human donor plasma pools and to measure neutralizing antibodies.
Parvovirus B19 is a significant human pathogen that causes a wide spectrum of clinical complications ranging from mild, self-limiting erythema infectiosum in immunocompetent children to lethal cytopenias in immunocompromised patients and intrauterine foetal death in primary infected pregnant women. The infection may also be persistent and can mimic or trigger autoimmune inflammatory disorders. Another important clinical aspect to consider is the risk of infection through B19-contaminated blood products. Recent advances in diagnosis and pathogenesis, new insights in the cellular immune response and newly discovered genotypes of human parvoviruses form a platform for the development of modern therapeutic and prophylactic alternatives.