Comparisons of the cellular immune response of fish vaccinated by immersion and injection of Vibrio anguillarum.

Abstract

The cellular immune response of rainbow trout Salmo gairdneri immunized by immersion or injection with Vidrio anguillarum bacterin was investigated using the passive antibody producing cell assay and passive antidody rosette-forming cell assay. Antibody-producing cels (plaqueforming cell: PFC) were rarely detected in the anterior kidney and spleen of raindow trout immunized by immersion. PFCs were detected in fish immunized by injection and reached the maximum level on the 13th day after immunization. The number of antigen-bingding cells (rosette-forming cells: RFCs) increased rapidly in the anterior kidney and spleen of rainbow trout vaccinated by immersion or injection. The RFC reached the maximum level on the 11th day after immunization. After that the number of RFCs gradually decreased until it reached the same level as that in non-immunized fish on the 28th day. The hemagglutinating antibody of the serum against V. anguillarum of fish vaccinated by immersion tended to be as low as the serum of non-vaccinated fish. However, the hemagglutinating antibody in fish vaccinated by injection was detected first on the 13th day after immunization. The maximum value of the titer was reached on the 28th day after immunization.