Detection of antigens of the mouse mammary tumor (MTV) and murine leukemia virus (MuLV) in cells of cultures derived from mammary tumors of mice of several strains

Abstract

A number of tissue cultures of mouse mammary tumors were studied for the presence of the mouse mammary tumor virus (MTV) and of the murine leukemia virus (MuLV) antigens. Mixed hemadsorption reaction (MHA) was used for detection on the cell surface and indirect immunofluorescence (IF) on fixed cells for detection of antigens of the two viruses within the cells. Three rabbit anti-MTV sera, three rat anti-MuLV sera, and one rabbit anti-FeLV (feline leukemia virus) serum were used in these studies. The same cells of a 4-year-old cell line derived from a spontaneous mammary tumor of an RIII/Dm mouse strain, designated as Dmochowski-Williams line (D-W line), were found positive at the same time for the antigens of the two oncogenic RNA viruses (MTV and MuLV) in the cytoplasm (IF) and on the cell surface (MHA). Several cell lines derived from induced BALB/c/Dm mammary tumors were found negative on the cell surface (by MHA) and in the cytoplasm (by IF) for MTV antigens. Some of the BALB/c/Dm mammary tumor cell lines negative for MTV antigens were found positive for MuLV antigens (by both MHA and IF). The antigens of MTV and MuLV were found by IF in the cytoplasm of the tumor cells. No nuclear fluorescence was observed. The shared antigen of mammalian leukemia-sarcoma viruses (MuLV-gs3) was found by IF in the cytoplasm of mammary tumor cells producing type C virus particles. MuLV-gs1 and MuLV-gs3 antigens were not found in mammary tumor cell lines shown to be positive only for MTV. Mammary tumor cell lines found positive by IF for MTV and/or MuLV antigens present in the cytoplasm were also positive by MHA for MTV and/or MuLV antigens present on the cell surface. The anti-MuLV-gs1 and anti-MuLV-gs3 sera gave positive IF test (cytoplasmic antigens) and negative MHA test (cell surface antigens) with cell lines shown to contain type C virus particles. The same cell lines were positive by both MHA and IF tests with a polyvalent anti-MuLV serum.