Regulatory factors of lymphocyte-lymphocyte interaction. I. Con A-induced mitogenic factor acts on the late G1 stage of T-cell proliferation.
DNA synthesis in murine lymphocytes was augmented by a soluble factor in the supernatant of serum-free cultures of syngeneic spleen cells activated with concanavalin A (Con A). This so-called mitogenic factor (MF), which is probably identical with interleukin II, partially purified by DEAE-cellulose and Sephadex G-75 chromatography, is a fairly homogeneous molecule of 17-25 X 10(3) daltons. By using partially purified MF, the role of MF in lymphocyte proliferation was investigated. Pretreatment of lymphocytes with Con A for the first 3 hr of culture, which does not in itself induce cell proliferation, markedly augmented the effect of MF. The presence of MF, however, is necessary only in a restricted stage(s) of lymphocyte proliferation. The addition and removal of MF at various times during culture showed that MF exerts its effect on a process which occurs 3-6 hr before the beginning of DNA synthesis. These results strongly suggest that MF regulates the proliferation of mitogen-stimulated lymphocytes by acting on a restricted stage(s) of the cell cycle.
D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D007376:Interleukin-2 / Q000302:isolation & purification / Q000494:pharmacology*; D007399:Interphase; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D013601:T-Lymphocytes / Q000166:cytology* / Q000502:physiology
D007376:Interleukin-2; D008222:Lymphokines; D003208:Concanavalin A; D004247:DNA