title: Efficacy of a live Cryptobia salmositica vaccine, and the mechanism of protection in vaccinated rainbow trout, Oncorhynchus mykiss, against cryptobiosis.
abstract: An attenuated strain of Cryptobia salmositica was used as a live vaccine to protect rainbow trout, Oncorhynchus mykiss, against cryptobiosis. Fish immunized with 1.0 x 10(4) or 5.5 x 10(4) attenuated C. salmositica per fish were protected 3 weeks after immunization; however, this period was reduced to 2 weeks if fish were vaccinated with 1.0 x 10(5) attenuated parasites per fish. Fish were still protected at 6, 12 and 24 months after vaccination. Complement fixing antibodies in the blood of immunized fish lysed C. salmositica under in vitro conditions. The titre of complement fixing antibodies in vaccinated fish increased rapidly 1-2 weeks post-challenge. In vitro phagocytosis was enhanced by antiserum and by activated macrophages from vaccinated fish. There was also evidence of antibody independent and antibody dependent cell-mediated cytotoxicity in vaccinated fish.
authors.affiliation: Department of Zoology, University of Guelph, Ont., Canada.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: P T
authors.initials: PT
authors.lastname: Woo
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000032:analysis; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology; D003168:Complement Fixation Tests / Q000662:veterinary; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control*; D016830:Kinetoplastida / Q000276:immunology*; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D017686:Oncorhynchus mykiss / Q000276:immunology / Q000469:parasitology*; D010587:Phagocytosis; D011528:Protozoan Infections / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control; D011529:Protozoan Infections, Animal; D016052:Protozoan Vaccines / Q000008:administration & dosage; D014611:Vaccination / Q000662:veterinary*; D014613:Vaccines, Attenuated / Q000008:administration & dosage
chemical_list: D000913:Antibodies, Protozoan; D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated