CD-80(B7-1) EXPRESSION ON HUMAN TUMOR-CELL LINES AND ITS COSTIMULATORY SIGNALS FOR T-CELL PROLIFERATION AND CYTOKINE PRODUCTION

Objective To investigate CD 80 expression on human tumor cell lines an d establish stable CD 80 expression transfectants to illustrate CD 80 costimulation on the T cell proliferation and cytokine production. Met hods Raji, MDA-453, MCF-7, Hela, 3AO, MKN-45 and EBV transformed B cel l were detected for CD 80 expression by RT-PCR. CD 80 cDNA subcloned t o retrovirus vector pLXSN, with them stable CD 80 transfectanants were established. With specific mAb BB1 and FAGS assay, the expression of CD 80 were detected. Anti-CD3 induced T lymphocyte proliferation and I L-2, IFN-r production were performed to evaluate CD 80 costimulatory a ctivity in the presence of calcium ionophore A23187 and phorbol ester PMA. Results CD 80 (B7-1) expression of MDA-453, MCF-7, Hela, 3AO, MKN -45 was negative, and that of Raji and EBV transformed B cell was posi tive by RT-PCR and FAGS methods. Cocultured with CD 80 transfected hum an breast carcinoma cell line MDA-453, anti-CD3 induced T cells prolif eration and cytokine production were significantly increased in the pr esence of A23187 and PMA, but not with parental MDA-453. Conclusions C D 80 expression is absent on most human tumor cell line except for Raj i and EBV transformed B cell. Full activation of T cell needs CD 80 co stimulation. Influence of CD 80 costimulation on cytokine production i s mainly regulated via IL-2 and IFN-r.