THE ENHANCEMENT OF CELL-SURFACE ICAM-1 AND HLA CLASS-I ANTIGENS IN HUMAN GASTRIC-CANCER CELL-LINES BY IFN-GAMMA

Cytotoxic lymphocytes, including natural killer cells, lymphokine-acti vated killer cells, and cytotoxic T lymphocytes, adhere to and lyse ca ncer cells by recognizing cell surface antigens. Among the cell surfac e antigens, intercellular adhesion molecule-1 (ICAM-1.) and HLA class I antigen are important for the cytotoxic activity of lymphocytes. The ICAM-1 and HLA class I antigen were examined in gastric cancer cell l ines MKN-28 and MKN-45 by flow cytometry to determine whether their ex pression on the cell surface is enhanced by interferon gamma (IFN-gamm a). The cell expression rate [stained cells/10(4) cells x 100(%)] was only 10% in ICAM-1 and about 20% in HLA class I antigen without lFN-ga mma, but reached 70% in ICAM-1 and up to 60% in HLA class I antigen af ter incubation with IFN-gamma for 24-96h. This enhanced expression of cell surface ICAM-1 and HLA class I antigen by IFN-gamma might increas e sensitivity for cytotoxic lymphocytes.