The effect of interferon-γ and tumor necrosis factor-α on the expression of ICAM-1 and HLA-DR molecules on cells of a human germ cell neoplasm and their susceptibility to lysis by lymphokine-activated killer cells

The ICAM-1 molecule plays a role in the interaction of NK cells with a variety of tumor cells, including carcinoma, melanoma and glioblastoma cells. In the present study, we analyzed the effect of IFN-γ and TNF-α on both the expression of HLA-DR and ICAM-1 molecules on HGCN (Germa-2), and on their susceptibility to lysis by LAK cells. Our results show that 1000 U/ml IFN-γ induced a substantial increase in the expression of both ICAM-1 molecules and HLA-DR on the cell surface, while the effect of TNF-α on the expression of these molecules was substantially less prominent. When Germa-2 cells, previously exposed to 1000 U/ml IFN-γ, were employed as target cells in a 4-hour ⁵¹Cr release assay, a statistically significant increase in the lysis by LAK cells was noted. These results show that in the presence of IFN-γ, Germa-2 tumor cells undergo modulation which affects both the expression of ICAM-1 and HLA-DR molecules as well as their susceptibility to lysis by LAK cells.