Human intestinal mononuclear cells: I. Investigation of antibody-dependent, lectin-induced, and spontaneous cell-mediated cytotoxic capabilities

Abstract

Cytotoxic mononuclear cells may mediate inflammatory bowel disease but have not been demonstrated in human intestinal mucosa. Therefore, we have examined human intestinal specimens for the presence of cytotoxic mononuclear cells and lymphocytes. Using a sequential dithiothreitol-EDTAcollagenase technique, we examined mononuclear cells obtained from mucosa of 37 intestinal specimens consisting of inflammatory bowel disease or normal control tissue adjacent to tumor or diverticular disease, all obtained at surgery. Surface characteristics revealed a mean of 7% ± 1% Fc receptor bearing cells for control colon and 6% ± 2% for inflammatory bowel disease intestine. Lectin-induced cellular cytotoxicity with human red blood cells as targets was seen with unseparated mononuclear cells and macrophage depleted lymphocytes from peripheral blood (64% and 46%, respectively), control colons (22%, 19%) ulcerative colitis colons (29%, 18%), and Crohn's intestinal specimens (43%, 29%). Antibody-dependent cellular cytotoxicity with chicken red blood cells as targets was also seen with unsepa rated mononuclear cells and macrophage-depleted lymphocytes from peripheral blood (44% and 45%, respectively) control colons (15%, 24%), ulcerative colitis colons (24%, 20%), and Crohn's intestinal specimens (17%, 13%). In contrast, using Chang cell lines as targets, antibody-dependent cellular cytotoxicity was observed with peripheral blood mononuclear cells but not with control or inflammatory bowel disease intestinal cells. Spontaneous cell-mediated cytotoxicity against Chang or K562 cell lines was also not observed with intestinal cells. These experiments demonstrate that Fc-receptor bearing mononuclear cells are present in control and IBD human intestinal mucosa. Furthermore, lamina propria lymphocytes from control and inflammatory bowel disease intestine mediate lectin-induced cellular cytotoxicity against human red blood cells and antibody-dependent cellular cytotoxicity against chicken red blood cells, but do not mediate cytotoxicity against cell line cells.