Effect of autoantibody against follicle stimulating hormone (Fsh) induced by DNA vaccine in rainbow trout Oncorhynchus mykiss

In this study, effects of DNA vaccine encoding rainbow trout (Oncorhynchus mykiss) follicle stimulating hormone (Fsh) gene (pCI-Fsh) was evaluated. pCI-Fsh was injected into the fish to analyze the specific antibody titer against Fsh and sexual maturation. The antibody titer against Fsh in the vector-injected fish was significantly higher than those in the PBS-injected fish at 13 and 146 days after injection. On the other hand, vitellogenin gene expression levels in the female fish and 11-ketoteststeron concentration in the male fish were not significantly different between the vector- and PBS-injected fish. In addition, gonad somatic index and body weight of the trout were not significantly different between the fish. These results suggested that the autoantibody induced by pCI-Fsh was not sufficient to inhibit sex steroidogenesis in the trout. •pCI-FSH vector induced anti-FHS antibody in rainbow trout.•Anti-FSH antibody titer increased in the immunized fish again just before spawning season.•Anti-FSH antibody had no influence on steroidogenesis in rainbow trout.