Development of DNA Vaccines against Mycolicibacterium cyprinidarum Isolated from Diseased Koi Carp

Abstract

We aimed to develop DNA vaccines against Mycolicibacterium cyprinidarum that are commonly isolated from diseased koi carp Cyprinus carpio. Major antigenic genes, Ag85B, Ag85C, Ag85D and ESAT-6 were cloned into a mammalian expression vector and used as DNA vaccines. Common carp were injected intramuscularly with each DNA vaccine individually, multiple mixtures of each DNA vaccine, PBS, or empty vector DNA. Cumulative survival rate after a bacterial challenge was 65.5% in PBS-injected group, while all fish survived from the challenge in the group co-immunized with the plasmids encoding Ag85B, Ag85C, Ag85D, and ESAT-6. The DNA vaccine cocktail may be a promising prevention method against M. cypridarum infection in koi carp aquaculture.