HUMAN HEPATOMA-CELLS EXPRESSING HLA CLASS-I MOLECULES STIMULATE PRIMARY RESPONSES OF PURIFIED CD8-LYMPHOCYTES( T)

In the present study, we investigated the ability of major histocompat ibility complex (MHC) class-I+ human hepatoma cell lines to induce pri mary proliferative responses of purified allogeneic CD8+ T lymphocytes . We found that HA22T/VGH and Li7A, but not HepG2 cells induced signif icant proliferation of CD8+ T cells and that these responses were depe dent on class I molecule expression. In blocking experiments carried o ut to identify the costimulatory signals involved, we found that anti- ICAM1 monoclonal antibodies drastically inhibited CD8+ T-cell prolifer ative responses. These findings suggest that transformed hepatocytes e xpressing HLA class I molecules may participate in anti-tumour immunos urveillance by the direct induction of cytotoxic T-cell responses thro ugh ICAM1-mediated adhesive interaction.