Control of proliferation in mitogen responsive human peripheral blood lymphocytes: restimulation of cells stimulated by sodium periodate.

Human peripheral blood lymphocytes are stimulated to a greater extent by sodium periodate when cells are incubated in medium containing human serum than when incubated in medium with fetal calf serum. NaIO4 STIMULATION CAN BE REVERSED BY TREATMENT WITH SODIUM BOROHYDRIDE BUT CELLS ALREADY COMMITTED TO DIVISION ARE NOT AFFECTED BY BOROHYDRATE TREATMENT. Maximal commitment to DNA synthesis of a NaIO4 oxidized cell suspens-on occurs after about 28 hr of incubation in medium. The committal time after periodate stimulation is identical to that after stimulation with concanavalin A. Cells treated with periodate and then reduced with borohydride immediately after oxidation are refractory to further per-odate stimulation. Cells stimulated with periodate and then incubated for 6 hr before treatment with borohydride can be restimulated with periodate, indicating a turnover of membrane sites in the 6 hr period. Periodate-stimulated cells divide only once in response to the stimulation. The progeny of cells which were stimulated with periodate can be restimulated by treatment with either periodate or concanavalin A.