title: In vitro cytotoxic effect of lymphocytes and their extracts in inflammatory bowel diseases. I.
abstract: From the sera of 20 patients with ulcerative colitis (U.C.) 10 patients with Crohn's Disease (C.D.) and 10 volunteers, lymphocytes were isolated and extracts of whole lymphocytes (T+B+K) and pure T lymphocytes were prepared. Whole lymphocyte extracts were further fractionated into fraction A containing mainly antibody and fraction B containing mainly membrane-bound receptors. The ability of various lymphocytes and their extracts to lyse allogeneic colonic epithelial cells in vitro was tested with and without the addition of 50 microgram of Common antigen (C.A.) used as a blocking agent. The percentage of cells lysed by whole lymphocytes correlated well with the severity of symptoms of the patients with U.C. Pure T lymphocytes were cytotoxic only in C.D. but not in U.C. Isolated extracts fractions A and B were not cytotoxic in active U.C. except when tested in combination. The addition of the Kunin antigen blocked the effect of lymphocytes from patients with active U.C. The results indicate differences in the mechanism of immunological activity of lymphocytes in U.C. and C.D. and show a direct relation of B lymphocytes and K cells to the cytotoxicity of U.C.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D003093:Colitis, Ulcerative / Q000276:immunology*; D003424:Crohn Disease / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology