Although schistosomicidal drugs and other control measures exist, the advent of an efficacious vaccine remains the most potentially powerful means for controlling this disease. In this study, native fatty acid binding protein (FABP) from Fasciola gigantica was purified from the adult worm's crude extract by saturation with ammonium sulphate followed by separation on DEAE-Sephadex A-50 anion exchange chromatography and gel filtration using Sephacryl HR-100, respectively. CD1 mice were immunized with the purified, native F. gigantica FABP in Freund's adjuvant and challenged subcutaneously with 120 Schistosoma mansoni cercariae. Immunization of CD1 mice with F. gigantica FABP has induced heterologous protection against S. mansoni, evidenced by the significant reduction in mean worm burden (72.3%), liver and intestinal egg counts (81.3% and 80.8%, respectively), and hepatic granuloma counts (42%). Also, it elicited mixed IgG1/IgG2b immune responses with predominant IgG1 isotype, suggesting that native F. gigantica FABP is mediated by a mixed Th1/Th2 response. However, it failed to induce any significant differences in the oogram pattern or in the mean granuloma diameter. This indicated that native F. gigantica FABP could be a promising vaccine candidate against S. mansoni infection.
Animals ; Antibodies, Helminth/immunology ; Fasciola/*chemistry ; Fatty Acid-Binding Proteins/*administration & dosage/immunology/isolation & purification ; Female ; Helminth Proteins/*administration & dosage/immunology/isolation & purification ; Humans ; Immunization ; Mice ; Mice, Inbred Strains ; Schistosoma mansoni/immunology/*physiology ; Schistosomiasis mansoni/immunology/parasitology/*prevention & control

OBJECTIVETo investigate the protective immunity induced by the anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum in mice.

METHODSAn orthogonal table L(16) (4 x 2(12)) was selected as the experimental design. Eight-week-old Kunming outbred mice (male and female) were randomly divided into 16 experimental groups and 2 control groups. Control groups were injected with SP2/0 ascites intraperitoneally. Mice from each group were infected with 100 +/- 2 cercariae of Schistosoma japonicum in the abdominal skin and were sacrificed on the thirtieth day postchallenge. Adult worms were recovered and counted by perfusion of the left ventricle-portal vein. The SP2/0 ascites injected mice were used as controls and the percentage of protection was calculated.

RESULTSActive immunization of mice with NP30 could produce protection levels ranging from 22.36% to 50.46% depending on the different immunity protocols. The best immunization protocol was established from the results.

CONCLUSIONSActive immunization with NP30 can induce a degree of protection to infection with Schistosoma japonicum cercariae and NP30 is a potential vaccine candidate against Schistosoma japonicum.

Analysis of Variance ; Animals ; Animals, Outbred Strains ; Antibodies, Anti-Idiotypic ; immunology ; therapeutic use ; Antibodies, Monoclonal ; immunology ; therapeutic use ; Female ; Male ; Mice ; Schistosoma mansoni ; immunology ; Schistosomiasis mansoni ; immunology ; parasitology ; prevention & control ; Treatment Outcome ; Vaccination

This study aimed to evaluate the efficacy of fructose-1,6-bis phosphate aldolase (SMALDO) DNA vaccination against Schistosoma mansoni infection using different routes of injection. The SMALDO has been cloned into the eukaryotic expression vector pcDNA3.1/V5-His TOPO-TA and was used in injecting Swiss albino mice intramuscularly (IM), subcutaneously (SC), or intraperitoneally (IP) (50 microg/mouse). Mice vaccinated with non-recombinant pcDNA3.1 served as controls. Each group was immunized 4 times at weeks 0, 2, 4, and 6. Two weeks after the last booster dose, all mice groups were infected with 80 S. mansoni cercariae via tail immersion. At week 8 post-infection, animals were sacrificed for assessment of parasitological and histopathological parameters. High anti-SMALDO IgG antibody titers were detected in sera of all vaccinated groups (P<0.01) compared to the control group. Both the IP and SC vaccination routes resulted in a significant reduction in worm burden (46.2% and 28.9%, respectively, P<0.01). This was accompanied by a significant reduction in hepatic and intestinal egg counts (41.7% and 40.2%, respectively, P<0.01) in the IP group only. The number of dead eggs was significantly increased in both IP and IM groups (P<0.01). IP vaccination recorded the highest significant reduction in granuloma number and diameter (54.7% and 29.2%, respectively, P<0.01) and significant increase in dead miracidia (P<0.01). In conclusion, changing the injection route of SMALDO DNA vaccination significantly influenced the efficacy of vaccination. SMALDO DNA vaccination via IP route could be a promising protective and anti-pathology vaccine candidate against S. mansoni infection.
Animals ; Antibodies, Helminth/blood ; Disease Models, Animal ; Female ; Fructose-Bisphosphate Aldolase/genetics/*immunology ; Histocytochemistry ; Immunoglobulin G/blood ; Injections, Intramuscular ; Injections, Intraperitoneal ; Injections, Subcutaneous ; Mice ; Parasite Load ; Schistosoma mansoni/enzymology/genetics/*immunology ; Schistosomiasis mansoni/immunology/parasitology/pathology/*prevention & control ; Vaccination/methods ; Vaccines, DNA/administration & dosage/genetics/*immunology ; Vaccines, Synthetic/administration & dosage/genetics/immunology