Influence of recombinant interferon-gamma QN the expression of MHC class I and class II antigens on four human colonic carcinoma cell lines

The occurrence of MHC class I and class II antigens on four human colonic carcinoma cell lines and the effect of recombinant interferon-gamma (rIFNg) on the expression of these antigens was investigated by immunofluorescent flow cytometry. The concentration of rIFNg which resulted in the largest increase in expression of class I and class II antigens was determined. Changes in the amount of MHC antigen on the membrane were indicated by a shift in the mean fluorescence intensity (MFI) of the cell population. Without addition of rIFNg, the COLO 206, COLO 320F and COLO 397 cell lines were class I positive although the COLO 206 cell line expressed less class I antigen than the other two lines. The HT-29 cell line expressed only a minimal level of class I antigen. Treatment with rIFNg increased the amount of class I antigen on these cell lines 5, 1.4, 2.5 and 20 times respectively. Maximum levels of class I antigen were found two days after treatment. Class I antigen expression returned to pre-treatment levels by day 8 in all but the HT-29 cell line, which maintained its increased level following a single dose of rIFNg. All four cell lines had little or no class II antigens. Following treatment with rIFNg, DR antigen appeared on all four lines whereas DP and DQ antigens could be induced only on the 320F and 397 lines. The amount of class II antigen reached its peak two days after treatment and gradually decreased over the next 6 days of culture.(ABSTRACT TRUNCATED AT 250 WORDS)