In vitro cellular cytotoxicity for a human colon cancer cell line by mucosal mononuclear cells of patients with colon cancer and other disorders

Abstract

In vitro cellular cytotoxicity of mononuclear cells of intestinal mucosa and peripheral blood for a colon cancer cell target was measured in patients with colon cancer and other disorders requiring resection. Four‐ and 24‐hour cytotoxicity assays were conducted using selenium 75 (75Se)‐labeled RPMI‐4788 human colon cancer target cells grown in culture. In the cancer group mean cytotoxicity was 30.4% at 24 hours for peripheral blood effectors and 8.0% for effectors from normal mucosa. Values in patients with Crohn's disease were 10.4% for blood and 17.2% for effectors from normal mucosa, and 13.6% and 18.5%, respectively, for blood and abnormal mucosa. Values in patients with other diseases were 25% for blood and 14.7% for mucosa. Mean cytotoxicity at 4 hours did not exceed 6.4% for any group, and assays in autologous serum gave results similar to tests in calf serum. In additional studies, K 562 chronic leukemia cells were somewhat more sensitive to lysis than RPMI‐4788 by blood mononuclear cells, but there was no lysis of K 562 by mucosal populations that were cytotoxic for RPMI‐4788. There was no competitive inhibition by either target cell for the other. It was concluded that 75Se RPMI‐4788 colon cancer cells are suitable targets for evaluating in vitro cytotoxicity by intestinal mucosal cells and that mucosal cytotoxicity in patients with colon cancer is depressed compared to cytotoxicity by peripheral blood effectors.

Normal Inflammatory Bowel Disease Mucosa Conceals Alterations in Natural Killer Cell Activity

“…The latter cell line has been reported to be more sensitive for LPMC cytotoxicity than K-562 in studies performed by Beeken et al (18). Our observation and those reported by Beeken et al (18) and Taunk et al (26) indicate that the mucosal NK cell has a different profile of target cell recognition from its peripheral blood counterpart. The lower susceptibility of Caco-2 cells to NK activity in the short 4-h assay of the present study seems to be in accordance with previous findings using peripheral blood mononuclear effector cells (25).…”

“…Beeken et al (18) did not find differences in cytotoxicity levels between normal and abnormal mucosal tissue in Crohn's disease, which might favor our observation that even normal mucosa conceals alterations in NK activity in this disease, perhaps preceding inflammation. These observed abnormalities were strengthened by the findings that NK activity in Crohn's disease patients or ulcerative colitis patients were also higher or lower, respectively, than in the control carcinoma patients.…”

“…This was earlier described by Gibson et al (l), but curiously, it has not yet been introduced as a common procedure to study mucosal NK activity despite immunohistochemical and functional experiments demonstrating NK cells to be present in low proportions. Significant levels of cytotoxicity, however, were obtained not only by introducing high effector to target ratios but also by preincubating the effector cells, prolonging the assay duration (2,13,18), and through enriching for NK cells by panning (6). So far, most studies have reported difficulties in detecting NK activity in LPMC or LPL preparations, or only very low levels have been found when using regular (50:l) effector to target cell ratios (6, 12, 14, 15).…”

“…Another colon tumor target cell line, RPMI-4788, was used in studies by MacDermott et al (13). The latter cell line has been reported to be more sensitive for LPMC cytotoxicity than K-562 in studies performed by Beeken et al (18). The latter cell line has been reported to be more sensitive for LPMC cytotoxicity than K-562 in studies performed by Beeken et al (18).…”

The CD56 adhesion molecule is the major determinant for detecting non‐major histocompatibility complex‐restricted cytotoxic mononuclear cells from the intestinal lamina propria

“…In general, functional evaluation of NK activity was done using inflamed IBD mucosa compared with normal mucosa from carcinoma patients which made it inaccurate to discuss differences between normal and diseased mucosa. Beeken et al [30] found high levels of cytotoxicity in both normal and inflamed mucosa in Crohn's disease compared with LPMC isolated from mucosa from carcinoma patients. Our group earlier reported decreased cytotoxicity of LPMC isolated from the tumor lesion compared with adjacent normal mucosa [31].…”