title: Correlation between the presence of natural antitumor antibodies and activation of MuLV endogenous virus in BALB/c mice.
abstract: Individual 3-month-old or 12-month-old BALB/c mice, as well as 5-month-old nu/nu or nu/ + BALB/c mice, showed a direct correlation between the serum level of natural antitumor cytotoxic antibodies and the capacity of spleen cells to infect SC-1 cells permissive for murine ecotropic viruses. Pooled or individual sera from 3-month-old BALB/c mice, negative for the presence of natural antitumor cytotoxic antibodies and whose spleen cells were unable to infect the SC-1 cells, were negative both for SC-1 cells and SC-1 cells infected by MuLV. On the contrary, pooled or individual sera from 15-month-old BALB/c mice, positive for the presence of natural antitumor antibodies and with infecting spleen cells, were cytotoxic for infected SC-1 cells but not for the uninfected ones. The infection of SC-1 cells by MuLV could be inhibited by 3-month-old spleen cells, and this effect was suppressed by depriving the inhibiting spleen cells of T cells by means of an anti-Thy-1 antibody plus complement. The cells with infectious capacity did not belong to the T-cell compartment, as demonstrated by the lack of infection after passing the infecting spleen cells through an anti-Ig column, whereas T-deprivation did not modify the infectious capacity. A natural anti-gp70 monoclonal antibody, which exerted a complement-dependent cytotoxic effect on tumor cells, strongly inhibited the infection of the permissive SC-1 cells by MuLV.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology*; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D007075:Immunoglobulin M / Q000276:immunology; D009052:Leukemia Virus, Murine / Q000254:growth & development / Q000276:immunology*; D007942:Leukemia, Experimental / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology; D014775:Virus Activation
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D007075:Immunoglobulin M