Feline oncornavirus-associated cell-membrane antigen (FOCMA): distinction between FOCMA and the major virion glycoprotein.

Abstract

The humoral antibody response of feline leukemia virus (FeLV)-exposed cats to the FOCMA is directly correlated with immunosurveillance against tumor development under natural conditions. By means of membrane immunofluorescence and radioimmunoprecipitation, the antibody response to FOCMA was found independent of the antibody response to the major envelope and core proteins of FeLV, gp70 and p30. This was especially true for healthy viremic cats, where antigenemia with circulating FeLV gp70 and p30 apparently binds any free antibody to these proteins, but high levels of FOCMA antibody are often concurrently present. Exhaustive in vitro absorption of highly immune nonviremic serum with gp70 and p30 also failed to remove FOCMA antibody activity. FOCMA is apparently not 1 of these major FeLV structural proteins.