Activation of spleen cell lytic activity by the alkaloid thiophosphoric acid derivative: Ukrain.

Abstract

Ukrain is a semisynthetic compound consisting of alkaloids from Chelidonium majus L. conjugated to thiophosphoric acid, with immunomodulatory and therapeutic properties in cancer patients. The present in vitro studies demonstrate that Ukrain is an effective biological response modifier in that it augmented, by up to 48-fold, the lytic activity of spleen lymphocytes obtained from alloimmunized mice. The lytic activities of IL-2-treated spleen cells and peritoneal exudate lymphocytes were also increased significantly by the addition of Ukrain to the CML assay medium. The highest Ukrain-induced enhancement of spleen lymphocyte lytic activity in vitro was found to occur at 18 days after alloimmunization, was dose dependent and specific for the immunizing P815 tumor cells. Since Ukrain was present only during the CML assays, its mode of action is thought to be via direct activation of the effector cell's lytic mechanism(s).