Influence of Bestatin, a new immunomodulator, on various functions of human monocytes.

Bestatin, which is a chemically well-defined immunomodulator, was examined for its possible influence on various monocyte functions. It was observed that pretreatment of separated human blood monocytes with Bestatin did not change their chemotactic or random migration. In addition, the capacity of monocytes to reduce nitroblue tetrazolium or to inhibit growth of Chang cells was unchanged by Bestatin. Phagocytosis of yeast particles, however, was increased by pretreatment of monocytes with Bestatin in vitro and it was observed that oral administration of Bestatin to cancer patients augmented the phagocytic activity of blood monocytes in vitro.