Immunological Study of the Colonic Mucosal Cell Destruction in Ulcerative Colitis: Role of ADCC Mechanism

Lymphocyte cytotoxicity against rat colon epithelial cells which share the antigen-specificity with the human colon was examined in 30 cases of ulcerative colitis, using the ⁵¹Cr-release cytotoxicity assay. Lymphocyte cytotoxicity against rat colon cells was observed in the cases of ulcerative colitis, esp. in the active stage. This cytotoxicity was revealed to be mainly mediated by non-T cells. Antibody dependent cell-mediated cytotoxicity against the colon's cells was seen, using the sera of the patients and lymphocytes from healthy individual in the assay. The presence of anti-colon antibodies in these sera was demonstrated by analysis of the colon cells treated with the sera on a fluorescence activated cell sorter. All these results suggest that the mechanism of ADCC should play an important role in the destruction of the colonic cells in ulcerative colitis patients.