Antibodies to the envelope protein (gp70) of endogenous xenotropic and ecotropic leukemia viruses: Induction by immunization with leukemia cells

Abstract

Mice of different inbred strains varied in their immune response to endogenous leukemia viruses (MuLV). The ability of mice to produce antibodies against the gp70 proteins of xenotropic and ecotropic MuLV was to some extent dependent upon the level to which these mice naturally expressed their endogenous leukemia viruses. Three patterns of response were observed upon immunization with AKR leukemia cells: (1) Mice of low leukemic strains, which did not contain inducible ecotropic or xenotropic MuLV, produced antibodies that reacted with the gp70 proteins of both xenotropic and ecotropic MuLV; (2) mice of low leukemic strains, which contained low levels of ecotropic and inducible xenotropic MuLV, produced antibodies that reacted primarily with the gp70 proteins of ecotropic MuLV; and, (3) mice of high leukemic strains, which contained high levels of ecotropic and inducible xenotropic MuLV, failed to produce antibodies that reacted with the gp70 proteins of either xenotropic or ecotropic MuLV. Antibodies induced by immunization with leukemia cells reacted with type-specific antigenic determinants of the gp70 protein; by absorption analysis distinctive antigenic determinants could be identified on the gp70 proteins of BALB xenotropic, NZB xenotropic, and AKR ecotropic MuLV.