Immune response of the mouse to the major core protein (p30) of ecotropic leukemia viruses.

Sera from normal C57BL/6 mice contained low titers of antibodies against proteins of MuLV. Sera from C57BL/6 mice that were immunized with allogeneic leukemia cells sometimes contained high-titered antibodies against the p15 protein of MuLV; these antibodies detected group-specific antigenic determinants of the p15 protein, since reactions were observed with the p15 proteins of both AKR and Moloney viruses. In contrast, antisera prepared in C57BL/6 mice against the AKR leukemia K36 reacted strongly with the p30 protein of MuLV, as well as with p15. Antibodies in the C57BL/6 anti-AKR K36 sera detected group-specific antigenic determinants of the p30 protein; reactions were observed with the C57BL/6 anti-AKR K36 serum and the p30 proteins of both AKR and Moloney viruses. It was concluded that mice do have the capacity to respond immunologically to antigenic determinants of the MuLV p30 protein, although in most circumstances this is not observed.