Mitogenic activities in the protein fractions of crude drugs.

Eighteen different crude drugs were extracted with hot water and saline, and protein fractions were prepared from the extracts by ammonium sulfate precipitation. Mitogenic activities of the protein fractions were examined both on human peripheral blood lymphocytes and on mouse spleen cells. Potent mitogenic activities for both human and/or mouse lymphocytes were found in the protein fractions of four crude drugs, namely, Bupleuri radix, Pinelliae tuber, Sophorae radix, and Zedoariae rhizoma. Target specificities of these mitogens were investigated by using isolated T and B cells and lymphocytes from athymic nude mice. Sensitivity to protease digestion as well as water-soluble, ammonium sulfate precipitable nature assures that the substances responsible for the mitogenic activities are proteins.