Role of suppressor cells in feline leukemia virus-associated immunosuppression.

Protein from detergent-disrupted feline leukemia virus was found to suppress lymphocyte blastogenic responsiveness of peripheral blood mononuclear cells from normal cats. When suppressive doses of this protein were substituted for mitogen in the preactivation step of the concanavalin A-induced suppressor cell assay, significant suppression was observed in five of eleven cats tested. These results suggest that feline leukemia virus-associated immunosuppression may be mediated by a virus-induced suppressor cell.