Vibrio anguillarum antigen stimulates mitogenesis and polyclonal activation of salmonid lymphocytes

An antigen preparation of Vibrio anguillarum, a salmonid pathogen, acts as a potent in vitro mitogenic stimulator of splenic and pronephric (anterior kidney) lymphocytes from coho salmon (Oncorhynchus kisutch), chinook salmon (O. tshawytscha) and rainbow trout (Salmo gairdneri). This antigen (VA) is comparable in its mitogenic activity to Concanavalin A (Con A), Escherichia coli lipopolysaccharide (LPS), and phytohemagglutinin (PHA). VA gives peak mitogenic responses in coho five days after initiation of cell culture. VA also appears to be a nonspecific polyclonal activator as determined by the generation of plaque forming cells to trinitrophenyl (TNP) and fluorescein (FI) haptenic determinants. Chemical characterization is limited, but it appears that Vibrio LPS could be responsible for these activities.