Expression of the B7 - related molecule B7 - H1 by glioma cells: a potential mechanism of immune paralysis

Human glioblastoma is a highly lethal tumor that is known for its immune inhibitory capabilities.B7-homologue l(B7-H 1),a recently identified homologue of B7.1/2(CD80/86),has been described to exert costimulatoryand immune regulatory functions.We investigated the expression and the functional activity of B7-H 1 in humanglioma cells in vitro and in vivo.Although lacking B7.1/2(CD80/86),all 12 glioma cel1 1ines constitutivelyexpressed B7-H1 mRNA and protein.Exposure to IFN-gamma strongly enhanced B7-H 1 expression.Im-