Different peptides from hemorrhagic septicemia rhabdoviral proteins stimulate leucocyte proliferation with individual fish variation.

Trout leucocytes from most of the survivors of viral hemorrhagic septicemia virus (VHSV) infections were capable of in vitro proliferation (T-like response) when cultured in the presence of short synthetic peptides designed from the G and the N cDNA-derived protein sequences of VHSV, a virus with substantial economic impact in trout farms. In contrast, no significant proliferative responses were obtained for the above-mentioned peptides from leucocytes obtained from either noninfected or genetically VHSV-resistant trout. However, since the anamnestic recognition of particular peptides (epitopes) of the G and the N protein by trout leucocytes varies largely within the outbred trout population, larger VHSV protein fragments were also tested. The finding that recombinant G and N fragments carrying multiple epitopes are recognized by the majority of the individual trout surviving VHSV infections and with higher stimulation indexes suggests that the recombinant viral proteins could be used as vaccines given the outbred nature of the fish.