[show abstract][hide abstract] ABSTRACT: A pre-designed plasmid containing the gene encoding the second subunit of Echinococcus granulosus AgB8 (EgAgB8/2) was used to study the effect of the immunization route on the immune response in BALB/c mice. Mice were immunized with pDRIVEEgAgB8/2 or pDRIVE empty cassette using the intramuscular (i.m.), intranasal (i.n.) or the epidermal gene gun (g.g.) routes. Analysis of the antibody response and cytokine data revealed that gene immunization by the i.m. route induced a marked bias towards a T helper type 1 (Th1) immune response as characterized by high IFN-γ gene expression and a low IgG1/IgG2a reactivity index (R.I.) ratio of 0.04. The i.n. route showed a moderate IFN-γ expression but a higher IgG1/IgG2a R.I. ratio of 0.25 indicating a moderate Th1 response. In contrast, epidermal g.g. immunization induced a Th2 response characterized by high IL-4 expression and the highest IgG1/IgG2a R.I. ratio of 0.58. In conclusion, this study showed the advantage of genetic immunization using the i.m. route and i.n. over the epidermal g.g. routes in the induction of Th1 immunity in response to E. granulosus AgB gene immunization.
[show abstract][hide abstract] ABSTRACT: This study explores the immune response generated in BALB/c mice that were genetically immunized with the second subunit of antigen B of Echinococcus granulosus (EgAgB8/2). In addition, immunomodulation by co- delivery of IL-4 and IFN-γ cytokine genes was assessed. Following cloning of EgAgB8/2 gene to a pDRIVE- meIF4A1 expression vector, successful gene expression was proved in vivo and in vitro by RT-PCR and polyclonal antibody response. The generated antigen specific IgG of gene immunization reacted with the 8 and 36 kDa fractions of crude sheep hydatid fluid; while the native antigen immunization resulted in antibody production reactive to the 8, 16, 24, and 36 kDa fractions. Spleen cells of mice immunized with EgAgB8/2 gene (using gene gun) or intradermally with native AgB (nAgB) secreted moderate levels of IL-4 but not IFN-γ. Co- immunization with EgAgB8/2 and IL-4 gene elevated the relative expression of both cytokines, while co- immunization with IFN-γ gene elevated significantly the expression of this cytokine gene only. While, no IgG1 response was detected in mice immunized with EgAgB8/2 gene, those immunized with nAgB showed a significant IgG1 response. However, neither source alone induced IgG2a response. Immunization with EgAgB8/2 gene induced about four times higher IgG3 antibody titers than that induced by nAgB. Co- immunization with IL-4 or IFN-γ genes reduced or abolished the IgG3 levels, respectively. In contrast, such treatments elevated markedly IgG1 and IgG2a with a significantly higher IgG1 level in IL-4 gene treated mice. On the cellular level, IFN-γ gene coimmunization induced the highest spleen cell proliferation. Both cytokine genes restored the reduced levels of splenic CD8 cells in gene immunized animals to control levels. In conclusion, the expression of EgAgB8/2 gene in mice induced a Th2 type response characterized by splenocyte IL-4 gene expression associated with high IgG3 response. Co-immunization with cytokine genes elevated IgG1 and IgG2a levels but lowered IgG3 titer.
International Journal of Integrative Biology 11/2008;
[show abstract][hide abstract] ABSTRACT: Cystic echinococcosis (CE), an endemic cosmopolitan zoonotic helminthic disease caused by the larval stage of Echinococcus granulosus, lacks reliable diagnostic tools that fulfill the criteria of high sensitivity and specificity. Antigen B (AgB), a thermostable lipoprotein that constitutes a considerable fraction of the cystic hydatid fluid (HF), is being considered as a suitable source for vaccination and immunodiagnosis of CE due to its high specificity. Genetic immunization was used to immunize BALB/c mice with the second subunit of antigen B (EgAgB8/2) for the production of monoclonal antibodies (MAb). Fusion products between the spleen cells and myeloma cells produced six MAbs of the following isotypes: IgG2a (two clones), IgG2b (three clones), and IgM (one clone). The MAbs were tested for their specificity to crude sheep hydatid fluid (CSHF) versus other antigens prepared from other helminthic parasites including Toxocara canis, Acanthocheilonema viteae, Fasciola hepatica, Schistosoma mansoni, and Taenia. Five MAbs reacted with E. granulosus antigens, one showed cross reactivity with S. mansonia antigens, and one showed a high reactivity with E. granulosus but was cross reactive with all helminthic antigens tested. Using SDS-PAGE and immunoblotting under reducing conditions, all MAbs identified the four AgB subunits with molecular weights of 8, 16, 24, and 36 kDa. Further work on the specificity and sensitivity of these MAbs as well as their use in detecting circulating parasite antigens and in antigen purification will be assessed in future studies.
[show abstract][hide abstract] ABSTRACT: Infection of BALB/c mice with protoscoleces of Echinococcus granulosus constitutes a model for the study of secondary hydatidosis (SH) and the associated immune response in immunization and infection trials. This study aimed at testing the efficacy of the cytokine gene expression approach to modulate the immune response and the magnitude of cyst development in mice with secondary hydatidosis. At the time of cyst development (28 days post infection), mice were injected intramuscularly with an expression vector containing murine promoter and carrying the open reading frames of IFN-gamma, IL-12 (Th1 cytokines), or IL-4 (Th2 cytokine). Assessment of cyst load at 22 weeks of infection showed a significant reduction in cyst load in mice injected with IFN-gamma and IL-12 genes at 60% and 47%, respectively. In contrast, the IL-4-gene-injected mice displayed six times higher cyst load in comparison to control-infected mice (injected with empty plasmids). Parasite-specific IgG2a peaked in IL-12-gene-injected mice at week 7 of infection (3 weeks after gene transfection), whereas in IFN-gamma-gene-injected mice IgG2a started to elevate after week 9 and continued to increase steadily until the termination of the experiment (22 weeks post infection). In contrast, in IL-4-gene-transfected mice, the IgG1 elevation started after week 9 and continued steadily thereafter. In conclusion, a significant high protection rate against secondary hydatidosis in BALB/c mice was accompanied with the induction of Th1 response. Moreover, in vivo IL-12 gene expression induced earlier IgG2a in comparison to IFN-gamma.
Parasitology Research 06/2008; 102(6):1151-5. · 2.85 Impact Factor
[show abstract][hide abstract] ABSTRACT: Infection of BALB/c mouse with protoscoleces of Echinococcus granulosus constitutes a model for the study of secondary hydatidosis and the associated immune response in immunization and infection trials. The aims of this study were to induce a protective immunity against secondary hydatidosis using conventional vaccination approaches and to analyse the immune responses that accompany this protection. Mice immunized with antigen B (AgB), a component of crude sheep hydatid fluid (CSHF), showed a significant level of protection as indicated by a 98.3% reduction in cyst load. This reduction in cyst development was accompanied by a high concentration of interferon gamma secreted by antigen-stimulated spleen cells, as compared with those secreted by cells of mice immunized with CSHF or protoscoleces homogenate (PSH) antigens. In contrast, interleukin-4 was significantly higher in the supernatants of cells stimulated with CSHF or PSH compared with AgB (191.5, 195.7 and 127.5 pg, respectively). Kinetic analysis of immunoglobulin subclasses showed persistently high levels of IgG1 and IgG2a subclasses in immunized infected animals until 6 months of infection, whereas IgG3 showed a significant decline after 1 month of infection. In infected non-immunized control mice, all IgG subclasses showed a gradual increase after the first month of infection until the experiment termination (8 months after infection).
Parasitology Research 01/2006; 98(1):54-60. · 2.85 Impact Factor
[show abstract][hide abstract] ABSTRACT: An ELISA was used to determine the seroprevalence of cystic echinococcosis (CE), caused by Echinococcus granulosus, in representatives of the rural-agricultural, semi-bedouin and bedouin communities of Jordan. The knowledge, attitudes and practices (KAP) pertaining to the transmission of CE in such communities were also investigated. In the ELISA, serum samples from 2388 subjects were tested for IgG antibodies reacting with antigens in crude sheep hydatid fluid (CSHF). The rural-agricultural subjects were significantly more likely to be seropositive (11.4%) than the semi-bedouin (5.0%) or bedouin (3.7%), but male and female subjects were equally likely to be seropositive. Among the rural-agricultural and semi-bedouin subjects, those aged 11-20 years were most likely to be seropositive. Among the bedouin subjects, however, seroprevalence was highest for those aged 31-40 years. When the distribution of 59 seropositive subjects detected within 36 rural-agricultural households was investigated, 12 (33.3%) of the households were each found to have at least two seropositive members. Immunoblotting indicated that 27.1% of the seropositive rural-agricultural subjects showed immunoreactivity to at least one of the CSHF antigen-B components (of 8-12, 16 and 24 kDa). The living conditions, practices and lifestyles of the rural-agricultural, semi-bedouin and bedouin communities favour the spread of CE in Jordan and warrant an effective programme for the control of the disease.
Annals of Tropical Medicine and Parasitology 08/2003; 97(5):511-20. · 1.31 Impact Factor
[show abstract][hide abstract] ABSTRACT: A retrospective follow-up study on the surgical incidence of cystic echinococcosis (CE) was carried out in major governmental, military and private hospitals throughout Jordan between 1994 and 2000. A total of 472 cases were recorded over the 7-year period and an overall mean annual surgical incidence (MASI) of 2.3 per 100,000 inhabitants was estimated. The highest number of surgical cases was recorded in hospitals of the middle region of the country. The highest MASI (3.6 per 100,000) was found in the southern region while the lowest (1.4 per 100,000) was in the northern region of the country. Taking into consideration the population size and the origin of surgically confirmed cases of each region, a relative surgical index (RSI) was calculated at which the highest (RSI=3.4) was among cases originated from the southern region and the lowest (RSI=0.7) was among those originated from the middle region of Jordan. The northern region and desert areas (badia) showed comparable RSI at 1.0 and 1.1, respectively. Males younger than 15 years of age showed significantly higher surgical incidence than females of comparable age at a ratio of 1.6:1, whereas the number of female cases of different age groups over 15 years of age was consistently higher than that of males at a ratio of 1.25-2.5:1.0. The liver was the primary site of cyst development in 69.4% of the cases and the lung involvement accounted for 13.3% of the cases. Diagnosis of CE in Jordan relies mostly on imaging methods with serological techniques being rarely used for diagnosis. The frequency of CE recurrence was 27.5% of the cases, which may be attributed to the low use of chemotherapeutic antihelminthics among surgically treated cases.
[show abstract][hide abstract] ABSTRACT: A total of 112 stray and semi-stray dogs (Canis familiaris) from four different geographical areas in northern and middle Jordan were necropsied to evaluate the prevalence and intensity of intestinal helminthiasis. Of these, 33 dogs (29.5%) were infected with Echinococcus granulosus and 61 (54.5%) with other Taenia species. Other cestodes found included Dipylidium caninum in 36 dogs (32.1%), Diplopylidium in 6 dogs (5.4%), Mesocestoides sp. in 3 dogs (2.7%) and Joyuexiella in 1 dog (0.9%). Toxocara nematodes were found in 10 dogs (9.2%) and only 1 dog was positive for acanthocephalans. Among the dogs infected with E. granulosus, 8 dogs (24.2%) had a worm load higher than 1,000 worms. The ratio of infected male to female dogs was 1.9:1.0. Strain analysis of E. granulosus using random primers revealed the dominance of the G1 strain (sheep/dog strain) in the region. Only one dog harbored another E. granulosus strain, which resembled the G4 strain pattern.
Parasitology Research 07/2003; 90(3):187-91. · 2.85 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ultrasound image and morphological structure of hepatic cystic echinococcosis (CE) were analysed in 277 human cases (385 hepatic hydatid cysts). These included 65 CE cases from community surveys carried out between 1995 and 2000 in 3 countries (China, Mongolia and Jordan) and 212 cases from a clinical hospital survey from Xinjiang, China. A new simplified WHO ultrasound classification for human CE was assessed, and considered useful. It is proposed that type, size and number in particular need to be included in the ultrasound classification of hepatic CE. For comparative purposes 6 categories of type were classified in the study as Type 0 to Type 5 (T0-T5): T0, univesicular without pathognomonic signs; T1, univesicular with pathognomonic signs; T2, cysts with sagging or floating laminated membrane; T3, cysts containing daughter cysts; T4, solid mass or mixed cysts; and T5, cysts with partial or full calcifications. This differs from the WHO classification wherein Type T3 cysts (daughter cysts present) are considered a pathological stage to occur in general prior to the sagging or floating membrane (T2) stage. Recurrent hydatid cysts in the liver were also studied based on morphological structures observed directly from surgical intervention. Case follow-up over 1-5 years since endocystectomy in the community surveys indicated 10% (2/10) recurrence of cysts in the residual surgical cavity. Recurrent CE included 2 (2/4) cases after percutaneous treatment.
Transactions of the Royal Society of Tropical Medicine and Hygiene 01/2003; 97(2):203-11. · 1.82 Impact Factor
[show abstract][hide abstract] ABSTRACT: The surgical incidence of cystic echinococcosis (CE) due to Echinococcus granulosus was investigated in hospitals of the West Bank, Palestinian Authority between January 1990 and December 1997. Serum samples from school-children in Yata town, which showed the highest surgical incidence, were tested for anti-hydatid antibodies. A total of 390 surgically confirmed cases were recorded throughout the 8-year period, with an overall mean annual surgical incidence (MASI) of 3.1 per 100,000. A high MASI of 4.9, 5.0 and 5.1 per 100,000 was found in Hebron, Jericho and Bethlehem Governorates, respectively. Yata town, Hebron governorate, showed the highest MASI, at 16.8 per 100,000. The highest incidence was found in age groups 11-20 and 21-30 years, at 27.4% and 21.5% of the total number of cases. While there was no significant gender difference in the number of cases in the age groups of 20 years or less, the male to female case ratio was 1:3.2-4.1 in the older age groups. The liver was the most common site of hydatid cysts in 69.9% of cases. Lung cysts were predominant in younger age groups (20 years or less). The seropositivity for CE in the school-children of Yata was 2.4% and 2.1% using enzyme-linked immunosorbent assay and the indirect haemagglutination test, respectively. CE is a significant endemic disease throughout the West Bank. The disease is acquired early in life and is more prevalent among females than males. Behaviour and life-style favour the spread of the disease.
Parasitology Research 03/2002; 88(2):107-12. · 2.85 Impact Factor