Expression and regulation of CD40 on human hepatoma cell lines

Expression of MHC antigens and costimulatory molecules on tumor cells mediates tumor rejection by CD4+ and CD8+ T cells. CD40 acts as a B7 independent costimulatory signal for T cells and mediates an enhanced sensibility for CD95 mediated apoptosis in different carcinoma cell lines. We investigated the expression of CD40 and its regulation by cytokines on human hepatoma cell lines. Hep 3B, Hep G2, and SK-Hep-1 were stimulated for 48 hours with TNF-~t or IL-113 in concentrations from 0.1-10ng/ml or IFN-~/ (1-1000 U/ml) or a combination of TNF-~ (1 ng/ml) and IFN-7 (100 U/ml)i Surface expression of CD40 and CD54 was investigated by direct immunofluorescence staining and flow cytometry. The mRNA expression of CD40 was monitored by RT-PCR. The table shows the results of flow cytometric analysis demonstrated as percentage (%) of CD40 positive ceils.