Blocking of cell-mediated immunity to Moloney murine sarcoma virus-transformed cells by lactate dehydrogenase virus-antibody complex.
The enhancement of Moloney murine sarcoma virus (M-MuSV) tumor growth in BALB/c mice previously infected with lactate dehydrogenase virus (LDV) was shown to depend on the timing of the inoculations. Mice infected with LDV either 3 or 4 days prior to the M-MuSV inoculations demonstrated enhanced tumor growth, whereas mice infected simultaneously with LDV and M-MuSV or with LDV 30 days prior to M-MuSV challenge did not demonstrate M-MuSV tumor enhancement. Circulating immune complexes (CIC) were isolated from serum pools of LDV-infected mice. IgM-containing CIC were isolated only between 3 and 9 days post LDV infection. CIC containing IgG1 were isolated only between days 6 and 13, whereas IgG2--containing CIC were not detected until 18 days post LDV infection. Coincubation of isolated immune complexes (IC) with M-MuSV-sensitized cytotoxic lymphocyte-transformed and M-MuSV-transformed target cells produced a 56% reduction in M-MuSV-specific cytotoxicity, with LDV-antibody IC isolated from the sera of mice 11 days post LDV infection. CIC isolated from the sera of mice 5 days and 25 days after infection with LDV demonstrated 11 and 9% reductions in M-MuSV cytotoxicity, respectively. LDV-antibody IC composed of IgG1 antibody may act as blocking factors to M-MuSV-sensitized lymphocytes in vitro and may be responsible for the transient M-MuSV tumor enhancement observed in dually infected mice.
D000818:Animals; D000936:Antigen-Antibody Complex / Q000302:isolation & purification*; D002472:Cell Transformation, Viral; D003602:Cytotoxicity, Immunologic; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000032:analysis; D007772:Lactate dehydrogenase-elevating virus / Q000276:immunology*; D008214:Lymphocytes / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008979:Moloney murine leukemia virus; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000473:pathology; D013997:Time Factors; D014412:Tumor Virus Infections
D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G