Oscillation of cell surface charge of human peripheral blood lymphocytes after stimulation with concanavalin A

Lymphocytes isolated from human peripheral blood were incubated with concanavalin A (Con A), and relative changes in cell surface charge were monitored by measuring cell electrophoretic mobility. Kinetic studies showed a time lag of 2.5 hr between exposure to Con A and development of a significant change in cell surface charge. The possible involvement of de novo synthesis of a factor was suggested by the following observations: 1) addition of the protein synthesis inhibitor, puromycin, abrogated the change in electrophoretic mobility; 2) supernatants obtained from cells incubated with Con A caused a mobility change in a separate group of lymphocytes not previously incubated with this mitogen; 3) supernatants obtained from cell suspensions treated with puromycin were inactive. The mobility response showed an oscillation of membrane charge ranging from a 1- to 1.5-hr period, which eventually disappeared after 8 hr at 37 degrees C. Cells at the minimum of the mobility oscillation were refractory to addition of active supernatants. This suggests the involvement at the lymphocyte surface of some cyclic metabolic process, or perhaps formation of receptor-factor complexes followed by endocytosis of these complexes with subsequent regeneration of the receptors on the cell surface.