LENTINAN AUGMENTS SKIN REACTION INDUCED BY BRADYKININ - ITS CORRELATION WITH VASCULAR DILATATION AND HEMORRHAGE RESPONSES AND ANTITUMOR ACTIVITIES

The effects of lentinan, an antitumor polysaccharide, on vascular reac tions against vasoactive mediators were investigated in murine systems . Lentinan augmented intradermal reactions against bradykinin. Inducti on of acute phase proteins (APP) and the vascular dilatation hemorrhag e (VDH) reaction on the ears have been reported to reflect the host re sponses to lentinan. The strain difference in the intensity of skin re actions coincided with those observed in VDH responses and with lentin an-induced antitumor effects against Sarcoma 180. Augmentation of skin reactions was not observed in T-cell-deficient mice. Inhibitors of li poxygenase, thrombin and plasmin which reduced skin reactions also dec reased the incidence of tumor necrosis positive mice among FBL-3-beari ng mice treated with lentinan. Furthermore, B10D2 mice treated with fl uorouracl (5-FU) and lentinan 10 days after S908.D2 transplantation sh owed complete tumor regression and augmented skin reactions, whereas a ugmentation of skin reactions and tumor regression were not observed i n mice treated with 5-FU and lentinan 32 days after tumor inoculation. Taken together, these results suggest that these vascular reactions m ight play crucial roles in antitumor effects of lentinan and that the skin reaction, the convenient method for investigating vascular reacti ons, is a promising tool to monitor host sensitivity to lentinan in an titumor responses.