Circulating antibodies to the feline leukemia virus and FOCMA in cats

Presence of antibodies to the structural proteins of the feline leukemia virus and the feline oncornavirus-associated cell membrane antigen FOCMA was analyzed in sera of 120 cats from household environments. In our experiments 35% of the sera tested were positive with the viable cells of FL-74 feline lymphoma cell line. On the other hand, only 5% of the feline sera reacted with FeLV from FL-74 cells in the solid phase RIA. Selected positive sera were analyzed for the presence of antibodies to the viral structural proteins of FeLV and FOCMA in lysates of FL-74 cells by radioimmunoprecipitation. Absorption of the selected sera (reacting with viable FL-74 cells) with disrupted FeLV had a negligible effect on the precipitating activity of the 70000 protein.