Effect of bestatin on in vitro responses of murine lymphocytes to T-cell stimuli.

Bestatin, a dipeptide protease inhibitor that has been reported to have immunomodulatory properties, was tested for its ability to augment the in vitro response of murine lymphocytes to allogeneic cells and to concanavalin A (Con A) or NaIO4 treatment. Bestatin augmented the response of spleen cells to allogeneic stimulation but was inhibitory in Con A and NaIO4 mitogenic assays. No augmentation of the allogeneic response was found if cells from responder and stimulator strains were genetically similar for the I region of the major histocompatibility complex. Bestatin did not restore the reduced mitogenic response of spleen cells from cyclophosphamide-treated animals. Although bestatin had no influence on interleukin activity once produced, it enhanced the production of interleukin activity in Con A cultures.