CONCANAVALIN-A-MEDIATED CHANGES IN THE ELECTROPHORETIC MOBILITY OF MURINE LYMPHOCYTES-T

Con A-mediated changes in the electrophoretic mobility (EPM) of murine splenic T lymphocytes were studied by the microelectrophoresis technique. After a 4-h treatment of lymphocytes with lectin the EPM increased significantly at a low concentration of Con A (5-20-mu-g/ml), whereas it decreased even lower than that of the untreated cells at a high concentration (50-mu-g/ml). It was shown that subsequent to the interaction of T lymphocytes with Con A (20-mu-g/ml) additional carboxylic groups of membrane proteins appear and the number of amino and sulfhydryl groups, effective at the electrophoretic surface of the cells, decreases. The EPM alterations did not depend on the Con A-induced protein synthesis. Con A increased the binding of calcium ions to lymphocyte membrane that may be found by radiometric method. The surface anionic groups formed the complexes with calcium ions with the apparent binding constant of about 15 M-1. The constant increased up to 50 M-1 after the lymphocytes were stimulated with Con A.