Marga van de Vegte-Bolmer

Leiden University Medical Centre, Leyden, South Holland, Netherlands

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Publications (26)187.89 Total impact

  • The Journal of infectious diseases. 05/2014;
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    ABSTRACT: The development of drugs and vaccines to reduce malaria transmission is an important part of eradication plans. The transmission reducing activity (TRA) of these agents is currently determined in the standard membrane feeding assay (SMFA) based on subjective microscopical read-outs and with limitations in up-scaling and throughput. Utilising a Plasmodium falciparum strain expressing the firefly luciferase protein, we present a luminescence based approach to SMFA evaluation that eliminates the requirement for mosquito dissections in favour of a simple approach where whole mosquitoes are homogenised and examined directly for luciferase activity. Analysis of 6860 Anopheles stephensi mosquitoes across 68 experimental feeds shows that the luminescence assay was as sensitive as microscopy for infection detection. The mean luminescence intensity of individual and pooled mosquitoes accurately quantifies mean oocyst intensity and generates comparable TRA estimates. The luminescence assay presented here could increase SMFA throughput so that 10-30 experimental feeds could be evaluated in a single 96-well plate. This new method of assessing Plasmodium infection and transmission intensity could expedite the screening of novel drug compounds, vaccine candidates and sera from malaria exposed individuals for TRA. Luminescence-based estimates of oocyst intensity in individual mosquitoes should be interpreted with caution.
    The Journal of Infectious Diseases 05/2014; · 5.85 Impact Factor
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    ABSTRACT: Effective control and eventual eradication of malaria drives the imperative need for clinical development of a malaria vaccine. Asexual parasite forms are responsible for clinical disease and death while apathogenic gametocytes are responsible for transmission from man to mosquito. Vaccines that combine antigens from both stages may provide direct protection and indirect benefit by reducing the force of infection. We constructed a chimeric antigen composed of a fragment of the Plasmodium falciparum (Pf) glutamate-rich protein fused in frame to a correctly folded fragment of Pfs48/45. The chimera was produced in Lactococcus lactis and induced robust antibody responses in rodents to the individual components. Specific antibodies showed strong transmission blocking activity against multiple Pf-strains in the standard membrane feeding assay and functional activity against asexual stages in the antibody dependent cellular inhibition assay. The combined data provide a strong rationale for entering the next phase of clinical grade production and testing.
    Vaccine 03/2014; · 3.77 Impact Factor
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    ABSTRACT: Volunteers immunized under chloroquine chemoprophylaxis with Plasmodium falciparum sporozoites (CPS) develop complete, long-lasting protection against homologous sporozoite challenge. Chloroquine affects neither sporozoites nor liver-stages, but kills only asexual forms in erythrocytes once released from the liver into the circulation. Consequently, CPS immunization exposes the host to antigens from both preerythrocytic and blood stages, and induced immunity might target either of these stages. We therefore explored the life cycle stage specificity of CPS-induced protection. Twenty-five malaria-naïve volunteers were enrolled in a clinical trial, 15 of whom received CPS immunization. Five immunized subjects and five controls received a sporozoite challenge by mosquito bites, whereas nine immunized and five control subjects received an i.v. challenge with P. falciparum-infected erythrocytes. The latter approach completely bypasses preerythrocytic stages, enabling a direct comparison of protection against either life cycle stage. CPS-immunized subjects (13 of 14) developed anticircumsporozoite antibodies, whereas only one volunteer generated minimal titers against typical blood-stage antigens. IgG from CPS-immunized volunteers did not inhibit asexual blood-stage growth in vitro. All CPS-immunized subjects (5 of 5) were protected against sporozoite challenge. In contrast, nine of nine CPS-immunized subjects developed parasitemia after blood-stage challenge, with identical prepatent periods and blood-stage multiplication rates compared with controls. Intravenously challenged CPS-immunized subjects showed earlier fever and increased plasma concentrations of inflammatory markers D-dimer, IFN-γ, and monokine induced by IFN-γ than i.v. challenged controls. The complete lack of protection against blood-stage challenge indicates that CPS-induced protection is mediated by immunity against preerythrocytic stages. However, evidence is presented for immune recognition of P. falciparum-infected erythrocytes, suggesting memory responses unable to generate functional immunity.
    Proceedings of the National Academy of Sciences 04/2013; · 9.74 Impact Factor
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    ABSTRACT: Malaria transmission blocking vaccines (TBVs) are considered an effective means to control and eventually eliminate malaria. The Pfs25 protein, expressed predominantly on the surface of the sexual and sporogonic stages of Plasmodium falciparum including gametes, zygotes and ookinetes, is one of the primary targets for TBV. It has been demonstrated that plants are an effective, highly scalable system for the production of recombinant proteins, including virus-like particles (VLPs). We engineered VLPs (Pfs25-CP VLP) comprising Pfs25 fused to the Alfalfa mosaic virus coat protein (CP) and produced these non-enveloped hybrid VLPs in Nicotiana benthamiana plants using a Tobacco mosaic virus-based 'launch' vector. Purified Pfs25-CP VLPs were highly consistent in size (19.3±2.4 nm in diameter) with an estimated 20-30% incorporation of Pfs25 onto the VLP surface. Immunization of mice with one or two doses of Pfs25-CP VLPs plus Alhydrogel® induced serum antibodies with complete transmission blocking activity through the 6 month study period. These results support the evaluation of Pfs25-CP VLP as a potential TBV candidate and the feasibility of the 'launch' vector technology for the production of VLP-based recombinant vaccines against infectious diseases.
    PLoS ONE 01/2013; 8(11):e79538. · 3.73 Impact Factor
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    ABSTRACT: Mosquito feeding assays are important in evaluations of malaria transmission-reducing interventions. The proportion of mosquitoes with midgut oocysts is commonly used as an outcome measure, but in natural low intensity infections the effect of oocyst non-rupture on mosquito infectivity is unclear. By identifying ruptured as well as intact oocysts, we show that in low intensity P. falciparum infections i) 66.7-96.7% of infected mosquitoes experienced oocyst rupture between 11-21 days post-infection, ii) oocyst rupture led invariably to sporozoite release, iii) oocyst rupture led to salivary gland infections in 97.8% of mosquitoes, and iv) 1250 (IQR 313-2400) salivary gland sporozoites were found per ruptured oocyst. These data show that infectivity can be predicted with reasonable certainty from oocyst prevalence in low intensity infections. High throughput methods for detecting infection in whole mosquitoes showed that 18s PCR but not circumsporozoite ELISA gave a reliable approximation of mosquito infection rates on day 7 post-infection.
    Scientific Reports 01/2013; 3:3418. · 2.93 Impact Factor
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    ABSTRACT: There is much evidence that some pathogens manipulate the behaviour of their mosquito hosts to enhance pathogen transmission. However, it is unknown whether this phenomenon exists in the interaction of Anopheles gambiae sensu stricto with the malaria parasite, Plasmodium falciparum - one of the most important interactions in the context of humanity, with malaria causing over 200 million human cases and over 770 thousand deaths each year. Here we demonstrate, for the first time, that infection with P. falciparum causes alterations in behavioural responses to host-derived olfactory stimuli in host-seeking female An. gambiae s.s. mosquitoes. In behavioural experiments we showed that P. falciparum-infected An. gambiae mosquitoes were significantly more attracted to human odors than uninfected mosquitoes. Both P. falciparum-infected and uninfected mosquitoes landed significantly more on a substrate emanating human skin odor compared to a clean substrate. However, significantly more infected mosquitoes landed and probed on a substrate emanating human skin odor than uninfected mosquitoes. This is the first demonstration of a change of An. gambiae behaviour in response to olfactory stimuli caused by infection with P. falciparum. The results of our study provide vital information that could be used to provide better predictions of how malaria is transmitted from human being to human being by An. gambiae s.s. females. Additionally, it highlights the urgent need to investigate this interaction further to determine the olfactory mechanisms that underlie the differential behavioural responses. In doing so, new attractive compounds could be identified which could be used to develop improved mosquito traps for surveillance or trapping programmes that may even specifically target P. falciparum-infected An. gambiae s.s. females.
    PLoS ONE 01/2013; 8(5):e63602. · 3.73 Impact Factor
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    ABSTRACT: We established a new field clone of Plasmodium falciparum (Pf) for use in controlled human malaria infections (CHMI) and vaccine studies to complement the current small portfolio of Pf strains, primarily based on NF54. The Cambodian clone NF135.C10 consistently produced gametocytes and generated substantial numbers of sporozoites in Anopheles mosquitoes and diverged from NF54 parasites by genetic markers. In a CHMI trial, three of five volunteers challenged by mosquitoes infected with NF135.C10 and four of five challenged with NF54 developed parasitaemia as detected by microscopy. The two strains induced similar clinical signs and symptoms as well as cellular immunological responses.
    The Journal of Infectious Diseases 11/2012; · 5.85 Impact Factor
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    ABSTRACT: Plasmodium falciparum is transmitted to a new host after completing its sexual cycle within a mosquito. Developing vaccines against the parasite sexual stages is a critical component in the fight against malaria. We are targeting multiple proteins of P. falciparum which are found only on the surfaces of the sexual forms of the parasite and where antibodies against these proteins have been shown to block the progression of the parasite's life cycle in the mosquito and thus block transmission to the next human host. We have successfully produced a region of the Pfs230 antigen in our plant-based transient-expression system and evaluated this vaccine candidate in an animal model. This plant-produced protein, 230CMB, is expressed at approximately 800 mg/kg in fresh whole leaf tissue and is 100% soluble. Administration of 230CMB with >90% purity induces strong immune responses in rabbits with high titers of transmission-blocking antibodies, resulting in a greater than 99% reduction in oocyst counts in the presence of complement, as determined by a standard membrane feeding assay. Our data provide a clear perspective on the clinical development of a Pfs230-based transmission-blocking malaria vaccine.
    Clinical and vaccine Immunology: CVI 06/2011; 18(8):1351-7. · 2.60 Impact Factor
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    ABSTRACT: We have shown that immunity to infection with Plasmodium falciparum can be induced experimentally in malaria-naive volunteers through immunisation by bites of infected mosquitoes while simultaneously preventing disease with chloroquine prophylaxis. This immunity was associated with parasite-specific production of interferon γ and interleukin 2 by pluripotent effector memory cells in vitro. We aim to explore the persistence of protection and immune responses in the same volunteers. In an open-label study at the Radboud University Nijmegen Medical Centre (Nijmegen, Netherlands), from November to December, 2009, we rechallenged previously immune volunteers (28 months after immunisation) with the bites of five mosquitoes infected with P falciparum. Newly recruited malaria-naive volunteers served as infection controls. Our primary outcome was the detection of blood-stage parasitaemia by microscopy. We assessed the kinetics of parasitaemia with real-time quantitative PCR (rtPCR) and recorded clinical signs and symptoms. In-vitro production of interferon γ and interleukin 2 by effector memory T cells was studied after stimulation with sporozoites and red blood cells infected with P falciparum. Differences in cellular immune responses between the study groups were assessed with the Mann-Whitney test. This study is registered with ClinicalTrials.gov, number NCT00757887. Four of six immune volunteers were microscopically negative after rechallenge. rtPCR-based detection of blood-stage parasites in these individuals was negative throughout follow-up. Patent parasitaemia was delayed in the remaining two immunised volunteers. In-vitro assays showed the long-term persistence of parasite-specific pluripotent effector memory T-cell responses in protected volunteers. The four protected volunteers reported several mild to moderate adverse events, of which the most commonly reported symptom was headache (one to three episodes per volunteer). The two patients with delayed patency had adverse events similar to those in the control group. Artificially induced immunity lasts longer than generally recorded after natural exposure; providing a new avenue of research into the mechanisms of malaria immunity. Dioraphte Foundation.
    The Lancet 05/2011; 377(9779):1770-6. · 39.06 Impact Factor
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    ABSTRACT: Malaria is a serious and sometimes fatal mosquito-borne disease caused by a protozoan parasite. Each year, it is estimated that over one million people are killed by malaria, yet the disease is preventable and treatable. Developing vaccines against the parasite is a critical component in the fight against malaria and these vaccines can target different stages of the pathogen's life cycle. We are targeting sexual stage proteins of P. falciparum which are found on the surface of the parasite reproductive cells present in the mosquito gut. Antibodies against these proteins block the progression of the parasite's life cycle in the mosquito, and thus block transmission to the next human host. Transmission blocking vaccines are essential to the malaria eradication program to ease the disease burden at the population level. We have successfully produced multiple versions of the Pfs25 antigen in a plant virus-based transient expression system and have evaluated these vaccine candidates in an animal model. The targets are expressed in plants at a high level, are soluble and most importantly, generate strong transmission blocking activity as determined by a standard membrane feeding assay. These data demonstrate the feasibility of expressing Plasmodium antigens in a plant-based system for the economic production of a transmission blocking vaccine against malaria.
    Human vaccines 01/2011; 7 Suppl:191-8. · 3.14 Impact Factor
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    ABSTRACT: Sulfadoxine-pyrimethamine (SP) is currently the drug of choice for intermittent preventive treatment of Plasmodium falciparum both in pregnancy and infancy. A prolonged parasite clearance time conferred by dhfr and dhps mutations is believed to be responsible for increased gametocyte prevalence in SP treated individuals. However, using a direct feeding assay in Mali, we showed that gametocytes present in peripheral venous blood post-SP treatment had reduced infectivity for Anopheles gambiae sensu stricto (ss) mosquitoes. We investigated the potential mechanisms involved in the dhfr and dhps quintuple mutant NF-135 and the single dhps 437 mutant NF-54. Concentrations of sulfadoxine (S) and pyrimethamine (P) equivalent to the serum levels of the respective drugs on day 3 (S=61 microg/ml, P=154.7 ng/ml) day 7 (S=33.8 microg/ml, P=66.6 ng/ml) and day 14 (S=14.2 microg/ml, P=15.7 ng/ml) post-SP treatment were used to study the effect on gametocytogenesis, gametocyte maturation and infectivity to Anopheles stephensi mosquitoes fed through an artificial membrane. The drugs readily induced gametocytogenesis in the mutant NF-135 strain but effectively killed the wild-type NF-54. However, both drugs impaired gametocyte maturation yielding odd-shaped non-exflagellating mature gametocytes. The concomitant ingestion of both S and P together with gametocytemic blood-meal significantly reduced the prevalence of oocyst positivity as well as oocyst density when compared to controls (P<0.001). In addition, day 3 concentrations of SP decreased mosquito survival by up to 65% (P<0.001). This study demonstrates that SP is deleterious in vitro for gametocyte infectivity as well as mosquito survival.
    International journal for parasitology 08/2010; 40(10):1221-8. · 3.39 Impact Factor
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    ABSTRACT: Naturally acquired immune responses against sexual stages of P. falciparum can reduce the transmission of malaria from humans to mosquitoes. These antigens are candidate transmission-blocking vaccines but little is known about the acquisition of sexual stage immunity after exposure to gametocytes, or their longevity and functionality. We conducted a longitudinal study on functional sexual stage immune responses. Parasitaemic individuals (n = 116) were recruited at a health centre in Lower Moshi, Tanzania. Patients presented with gametocytes (n = 16), developed circulating gametocytes by day 7 (n = 69) or between day 7 and 14 (n = 10) after treatment or did not develop gametocytes (n = 21). Serum samples were collected on the first day of gametocytaemia and 28 and 84 days post-enrolment (or d7, 28, 84 after enrolment from gametocyte-negative individuals). Antibody responses to sexual stage antigens Pfs230 and Pfs48/45 were detected in 20.7% (72/348) and 15.2% (53/348) of the samples, respectively, and were less prevalent than antibodies against asexual stage antigens MSP-1(19) (48.1%; 137/285) and AMA-1 (52.4%; 129/246)(p<0.001). The prevalence of anti-Pfs230 (p = 0.026) and anti-Pfs48/45 antibodies (p = 0.017) increased with longer duration of gametocyte exposure and had an estimated half-life of approximately 3 months. Membrane feeding experiments demonstrated a strong association between the prevalence and concentration of Pfs230 and Pfs48/45 antibodies and transmission reducing activity (TRA, p<0.01). In a longitudinal study, anti-Pfs230 and Pfs48/45 antibodies developed rapidly after exposure to gametocytes and were strongly associated with transmission-reducing activity. Our data indicate that the extent of antigen exposure is important in eliciting functional transmission-reducing immune responses.
    PLoS ONE 01/2010; 5(11):e14114. · 3.73 Impact Factor
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    ABSTRACT: The spread of drug resistance has been a major obstacle to the control of malaria. The mechanisms underlying drug resistance in malaria seem to be complex and multigenic. The current literature on multiple drug resistance against anti-malarials has documented PfMDR1, an ATP-binding cassette (ABC) protein, as an important determinant of resistance. In the Plasmodium falciparum genome, there are several ABC transporters some of which could be putative drug transporting proteins. In order to understand the molecular mechanisms underlying drug resistance, characterization of these transporters is essential. The aim of this study was to characterize and localize putative ABC transporters. In the plasmoDB database, 16 members of the P. falciparum ABC family can be identified, 11 of which are putative transport proteins. A phylogenetic analysis of the aligned NBDs of the PfABC genes was performed. Antibodies against PfMRP1 (PfABCC1), PfMRP2 (PfABCC2), and PfMDR5 (PfABCB5) were generated, affinity purified and used in immunocytochemistry to localize the proteins in the asexual stages of the parasite. The ABC family members of P. falciparum were categorized into subfamilies. The ABC B subfamily was the largest and contained seven members. Other family members that could be involved in drug transport are PfABCC1, PfABCC2, PfABCG1, and PfABCI3. The expression and localization of three ABC transport proteins was determined. PfMRP1, PfMRP2, and PfMDR5 are localized to the plasma membrane in all asexual stages of the parasite. In conclusion, 11 of the 16 ABC proteins in the P. falciparum genome are putative transport proteins, some of which might be involved in drug resistance. Moreover, it was demonstrated that three of these proteins are expressed on the parasite's plasma membrane.
    Malaria Journal 09/2009; 8:205. · 3.40 Impact Factor
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    ABSTRACT: An effective vaccine for malaria is urgently needed. Naturally acquired immunity to malaria develops slowly, and induction of protection in humans can be achieved artificially by the inoculation of radiation-attenuated sporozoites by means of more than 1000 infective mosquito bites. We exposed 15 healthy volunteers--with 10 assigned to a vaccine group and 5 assigned to a control group--to bites of mosquitoes once a month for 3 months while they were receiving a prophylactic regimen of chloroquine. The vaccine group was exposed to mosquitoes that were infected with Plasmodium falciparum, and the control group was exposed to mosquitoes that were not infected with the malaria parasite. One month after the discontinuation of chloroquine, protection was assessed by homologous challenge with five mosquitoes infected with P. falciparum. We assessed humoral and cellular responses before vaccination and before the challenge to investigate correlates of protection. All 10 subjects in the vaccine group were protected against a malaria challenge with the infected mosquitoes. In contrast, patent parasitemia (i.e., parasites found in the blood on microscopical examination) developed in all five control subjects. Adverse events were mainly reported by vaccinees after the first immunization and by control subjects after the challenge; no serious adverse events occurred. In this model, we identified the induction of parasite-specific pluripotent effector memory T cells producing interferon-gamma, tumor necrosis factor alpha, and interleukin-2 as a promising immunologic marker of protection. Protection against a homologous malaria challenge can be induced by the inoculation of intact sporozoites. (ClinicalTrials.gov number, NCT00442377.)
    New England Journal of Medicine 08/2009; 361(5):468-77. · 51.66 Impact Factor
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    ABSTRACT: Epigenome profiling has led to the paradigm that promoters of active genes are decorated with H3K4me3 and H3K9ac marks. To explore the epigenome of Plasmodium falciparum asexual stages, we performed MS analysis of histone modifications and found a general preponderance of H3/H4 acetylation and H3K4me3. ChIP-on-chip profiling of H3, H3K4me3, H3K9me3, and H3K9ac from asynchronous parasites revealed an extensively euchromatic epigenome with heterochromatin restricted to variant surface antigen gene families (VSA) and a number of genes hitherto unlinked to VSA. Remarkably, the vast majority of the genome shows an unexpected pattern of enrichment of H3K4me3 and H3K9ac. Analysis of synchronized parasites revealed significant developmental stage specificity of the epigenome. In rings, H3K4me3 and H3K9ac are homogenous across the genes marking active and inactive genes equally, whereas in schizonts, they are enriched at the 5' end of active genes. This study reveals an unforeseen and unique plasticity in the use of the epigenetic marks and implies the presence of distinct epigenetic pathways in gene silencing/activation throughout the erythrocytic cycle.
    Proceedings of the National Academy of Sciences 07/2009; 106(24):9655-60. · 9.74 Impact Factor
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    ABSTRACT: In the human malaria parasite Plasmodium falciparum, gametocyte maturation is a process remarkably longer than in other malaria species, accompanied by expression of 2-300 sexual stage-specific proteins. Disruption of several of their encoding genes so far showed that only the abundant protein Pfg27, produced at the onset of sexual differentiation, is essential for gametocyte production. In contrast with what has been previously described, here we show that P. falciparum pfg27 disruptant lines are able to undergo all stages of gametocyte maturation, and are able to mature into gametes. A fraction of Pfg27-defective gametocytes show, however, distinct abnormalities in intra- and extra-cellular membranous compartments, such as accumulation of parasitophorous vacuole-derived vesicles in the erythrocyte cytoplasm, large intracellular vacuoles and discontinuities in their trilaminar cell membrane. This work revises current knowledge on the role of Pfg27, indicating that the protein is not required for parasite entry into sexual differentiation, and suggesting that it is instead involved in maintaining cell integrity in the uniquely long gametocytogenesis of P. falciparum.
    Molecular Microbiology 07/2009; 73(2):180-93. · 4.96 Impact Factor
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    ABSTRACT: Malaria kills >1 million people each year, in particular in sub-Saharan Africa. Although asexual forms are directly responsible for disease and death, sexual stages account for the transmission of Plasmodium parasites from human to the mosquito vector and therefore the spread of the parasite in the population. Development of a malaria vaccine is urgently needed to reduce morbidity and mortality. Vaccines against sexual stages of Plasmodium falciparum are meant to decrease the force of transmission and consequently reduce malaria burden. Pfs48/45 is specifically expressed in sexual stages and is a well established transmission-blocking (TB) vaccine candidate. However, production of correctly folded recombinant Pfs48/45 protein with display of its TB epitopes has been a major challenge. Here, we show the production of a properly folded Pfs48/45 C-terminal fragment by simultaneous coexpression with four periplasmic folding catalysts in Escherichia coli. This C-terminal fragment fused to maltose binding protein was produced at medium scale with >90% purity and a stability over at least a 9-month period. It induces uniform and high antibody titers in mice and elicits functional TB antibodies in standard membrane feeding assays in 90% of the immunized mice. Our data provide a clear perspective on the clinical development of a Pfs48/45-based TB malaria vaccine.
    Proceedings of the National Academy of Sciences 04/2008; 105(11):4301-5. · 9.74 Impact Factor
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    ABSTRACT: Difficulties with inducing sterile and long lasting protective immunity against malaria with subunit vaccines has renewed interest in vaccinations with attenuated Plasmodium parasites. Immunizations with sporozoites that are attenuated by radiation (RAS) can induce strong protective immunity both in humans and rodent models of malaria. Recently, in rodent parasites it has been shown that through the deletion of a single gene, sporozoites can also become attenuated in liver stage development and, importantly, immunization with these sporozoites results in immune responses identical to RAS. The promise of vaccination using these genetically attenuated sporozoites (GAS) depends on translating the results in rodent malaria models to human malaria. In this study, we perform the first essential step in this transition by disrupting, p52, in P. falciparum an ortholog of the rodent parasite gene, p36p, which we had previously shown can confer long lasting protective immunity in mice. These P. falciparum P52 deficient sporozoites demonstrate gliding motility, cell traversal and an invasion rate into primary human hepatocytes in vitro that is comparable to wild type sporozoites. However, inside the host hepatocyte development is arrested very soon after invasion. This study reveals, for the first time, that disrupting the equivalent gene in both P. falciparum and rodent malaria Plasmodium species generates parasites that become similarly arrested during liver stage development and these results pave the way for further development of GAS for human use.
    PLoS ONE 02/2008; 3(10):e3549. · 3.73 Impact Factor
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    ABSTRACT: Pfs48/45, a member of a Plasmodium-specific protein family, displays conformation-dependent epitopes and is an important target for malaria transmission-blocking (TB) immunity. To design a recombinant Pfs48/45-based TB vaccine, we analyzed the conformational TB epitopes of Pfs48/45. The Pfs48/45 protein was found to consist of a C-terminal six-cysteine module recognized by anti-epitope I antibodies, a middle four-cysteine module recognized by anti-epitopes IIb and III, and an N-terminal module recognized by anti-epitope V antibodies. Refolding assays identified that a fragment of 10 cysteines (10C), comprising the middle four-cysteine and the C-terminal six-cysteine modules, possesses superior refolding capacity. The refolded and partially purified 10C conformer elicited antibodies in mice that targeted at least two of the TB epitopes (I and III). The induced antibodies could block the fertilization of Plasmodium falciparum gametes in vivo in a concentration-dependent manner. Our results provide important insight into the structural organization of the Pfs48/45 protein and experimental support for a Pfs48/45-based subunit vaccine.
    Journal of Biological Chemistry 06/2007; 282(23):17148-56. · 4.65 Impact Factor

Publication Stats

618 Citations
187.89 Total Impact Points

Institutions

  • 2014
    • Leiden University Medical Centre
      • Department of Medical Microbiology
      Leyden, South Holland, Netherlands
  • 2001–2014
    • Radboud University Medical Centre (Radboudumc)
      Nymegen, Gelderland, Netherlands
  • 2011–2013
    • Fraunhofer USA Center for Molecular Biotechnology (FhCMB)
      Delaware, United States
  • 2006–2012
    • Radboud University Nijmegen
      • • Department of Medical Microbiology
      • • Nijmegen Centre for Molecular Life Sciences
      • • Department of Molecular Biology
      Nijmegen, Provincie Gelderland, Netherlands