Expression of HLA class I and beta 2-microglobulin on human choriocarcinoma cell lines: induction of HLA class I by interferon-gamma.

The trophoblast cells which contact with maternal tissue express HLA class I either weakly or not at all. This phenomenon is beneficial for the protection of the fetus from immunological rejection by the mother. However, the mechanisms of reduced expression of HLA class I are unexplained. Therefore, we utilized choriocarcinoma cells to analyse the suppressive mechanisms to HLA class I expression in trophoblasts. In this paper we reported the heterogeneity of HLA class I expression in five choriocarcinoma cell lines. The levels of surface HLA class I molecules correlate approximately with mRNA of HLA class I heavy chain, and all choriocarcinoma cells produce moderate amounts of surface and secreted beta 2 microglobulin. It was also found that interferon gamma upregulates HLA class I molecules and mRNA in two choriocarcinoma cell lines, NUC1 and HCCM5.