Schistosoma mansoni: vaccination of mice with 10-krad-irradiated, cryopreserved schistosomules.
Protection against a Schistosoma mansoni cercarial challenge was evaluated in mice immunized with a vaccine composed of 10-krad-irradiated, cryopreserved schistosomules. The level of resistance induced in C57B1/6 or NMRI (CV) mice increased with the number of schistosomules injected. Up to 83% reduction in challenge worm burden was achieved when 5000 schistosomules were injected per mouse. Intramuscular injection of the vaccine was superior to subcutaneous. Multiple immunizations, up to 3 at 4-week intervals, did not increase the resistance induced by a single immunization. A high level of protection developed in as little as 2 weeks and was maintained through at least 12 weeks postimmunization. The vaccine irradiated with 10 krad from either a 60-cobalt or 137-cesium source induced equivalent levels of resistance, and no differences were found in the immunogenicity of vaccines comprised of organisms irradiated as cercariae or as 1- to 3-hr-old schistosomules. These findings are basic to the development of a cryopreserved, live vaccine against schistosomiasis of humans or domestic animals.
D000818:Animals; D004306:Dose-Response Relationship, Immunologic; D005615:Freezing; D051379:Mice; D008810:Mice, Inbred C57BL; D011309:Preservation, Biological; D012550:Schistosoma mansoni / Q000276:immunology* / Q000528:radiation effects; D012552:Schistosomiasis / Q000276:immunology / Q000517:prevention & control*; D014611:Vaccination