Colchicine inhibits phosphatidylinositol turnover induced in lymphocytes by concavalin A.

Abstract

RECENTLY colchicine has been shown to affect various membrane properties such as the lateral mobility of receptors and other surface membrane markers and the agglutination of different cell types. Many of the described phenomena also involve concanavalin A (con A); for example, phagocytosis by rabbit polymorphonuclear leukocytes (PMNs) leads to a selective depletion of con A binding sites which is prevented by colchicine1, con A inhibition of lymphocyte immunoglobulin receptor capping is reversed by colchicine2–4 and con A-induced aggregation of PMNs, fibroblasts and hepatoma cells is inhibited by colchicine5–7. In addition to these effects on membrane properties, colchicine also has been shown to inhibit con A-induced lymphocyte transformation at an early stage in the sequence of events leading to thymidine incorporation and blast transformation8,9. These various considerations led us to determine if colchicine could alter phosphatidylinositol (PI) turnover in lymphocytes since it is known that increased PI turnover is an early event induced by con A and other mitogenic lectins10–12.