Fresh colorectal tumor cells isolated from individual patients differ in their susceptibility to monocyte mediated cytotoxicity.

Abstract

Studies on monocyte/macrophage mediated cytotoxicity usually pertain to the use of cell lines that are liable to antigenic and structural changes. Therefore we compared monocyte mediated cytotoxicity against colorectal tumor cell lines (WiDR, HT29, SW620, and SW948) with fresh colorectal tumor cells from patients. Fresh tumor cells were isolated from surgical specimens by a short enzymatic treatment (Collagenase/DNAse). Monocytes were obtained from one healthy donor. Cytotoxicity was determined using the MTT-assay. Fresh colorectal tumor cells displayed a similar differential susceptibility to cytotoxic monocytes as cell lines. Cytotoxicity against fresh tumor cells ranged from 4.9% to 50.4% at E/T ratio 5 (n = 9). Activation of monocytes with Interferon-gamma (100 U/ml) induced an increase of 6.2% +/- 1.6 (n = 4, P = 0.06). In this study we demonstrate monocyte mediated cytotoxicity against colorectal tumor cells isolated from individual patients. This may be important in view of the development of adoptive immunotherapy and cell-directed immunotherapy.