title: Characterization of an early cytotoxicity-inducing factor in sera of Japanese quails after inoculation with Rous sarcoma virus.
abstract: By pre-treatment with serum of normal spleen cells used in the microcytotoxicity assay, a humoral factor which induces cytotoxic activity in normal spleen cells was demonstrated in about 40% of sera of Japanese quails as early as 3 days after inoculation with Rous sarcoma virus (RSV). This cytotoxicity-inducing activity was not present either in the IgM or the IgG fraction obtained by Sephadex gel filtration. In sera of quails with experimentally induced agammaglobulinemia, the cytotoxicity-inducing activity was demonstrated at the same frequency as in normal animals. Thus, it seems unlikely that the early cytotoxicity-inducing factor is an immunoglobulin. On the other hand, membrane fractions extracted with 3 M potassium chloride from the RSV-induced quail tumor (QT) cells used as target cells in the microcytotoxicity assay exhibited cytotoxicity-inducing activity. After spontaneous regression of an RSV-induced tumor the serum of the regressor quail contained antibodies specific to the QT cell extract. This serum removed the cytotoxicity-inducing activity of both QT cell extract and serum sampled 3 days after RSV inoculation. In contrast, serum without antibody to the QT cell extract failed to absorb the cytotoxicity-inducing activity of the extract. It is therefore suggested that soluble tumor antigens can act as an early cytotoxicity-inducing factor.
mesh_terms: D000361:Agammaglobulinemia / Q000276:immunology; D000818:Animals; D000951:Antigens, Neoplasm; D001358:Avian Sarcoma Viruses; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D002850:Chromatography, Gel; D003370:Coturnix / Q000097:blood / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D011784:Quail / Q000276:immunology*; D012513:Sarcoma, Experimental / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013934:Thymectomy
chemical_list: D000951:Antigens, Neoplasm