Isotype responses to candidate vaccine antigens in protective sera obtained from mice vaccinated with irradiated cercariae of Schistosoma mansoni.
In experimental schistosomiasis, sera of mice multiply vaccinated with radiation-attenuated cercariae of Schistosoma mansoni passively transfer resistance against cercarial challenge to naive mice. To further characterize these sera, we tested their protective capacities in two mouse strains (C57BL/6J and CBA/J) and compared the antigen-specific isotype compositions of the different protective sera by means of the enzyme-linked immunosorbent assay. By using an array of purified schistosomal antigens, the patterns of antibody titers and isotypes differed for each experimental group and antigen. In the most-protective C57BL/6J sera, high levels of immunoglobulin G1 (IgG1), IgG2a, and IgG2b bound to heat shock protein 70 and the integral membrane protein Sm23, whereas recognition of these antigens by less-protective CBA/J sera was lower. Glutathione S-transferase (GST) was recognized predominantly by IgM antibodies of all vaccinated groups, and a significant portion of this response was directed against carbohydrate epitopes. Antibodies specific for triosephosphate isomerase, paramyosin, and Sm32 (hemoglobinase) were present in less-protective sera and thus seem less relevant for passive transfer of resistance. The results of this study suggest a contribution of IgG antibodies specific for heat shock protein 70 and Sm23, and possibly a contribution of GST-specific IgM antibodies, to the protective effect of sera from C57BL/6J mice vaccinated with irradiated cercariae.
Richter
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Department of Tropical Public Health, Harvard School of Public Health, Boston, Massachusetts 02115.
Incani
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Harn
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D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000276:immunology*; D005260:Female; D005982:Glutathione Transferase / Q000276:immunology; D006360:Heat-Shock Proteins / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification; D007132:Immunoglobulin Isotypes / Q000097:blood*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D012550:Schistosoma mansoni / Q000276:immunology* / Q000528:radiation effects; D014305:Triose-Phosphate Isomerase / Q000276:immunology; D014611:Vaccination; D014612:Vaccines / Q000276:immunology*
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D006360:Heat-Shock Proteins; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D014612:Vaccines; D005982:Glutathione Transferase; D014305:Triose-Phosphate Isomerase