Modulation by glycyrrhizin of the cell-surface expression of H-2 class I antigens on murine tumour cell lines and normal cell populations.

Glycyrrhizin (GL), a saponin fraction of licorice with defined chemical structure, was shown to display a definite action in vitro augmenting the cell-surface expression of H-2 class I antigens as well as class I gene transcription on various tumour cell lines. The magnitude of augmentation was varied among eight different cell lines tested, but reached more than three times. It was also found that GL enhanced the expression of H-2Dd antigens in some normal cell populations in vivo. The augmentation of H-2 class I antigens on tumour cell lines in vitro was probably not mediated by the interferon, which might have been produced by the cultured cells. These findings may suggest a new immunopharmacological action of GL.