Role of ions in activation of human lymphocytes.
Phytohemagglutinin (PHA)-stimulated lymphocytes were cultured in media containing varying levels of K+, Mg2+, Ca2+. Cell activation was monitored by measuring nuclear diameter and by evaluating the area of nucleolus which reacted with silver nitrate. Decreasing extracellular K+ from normal levels (5.0 mM) to 14% (0.7 mM) and decreasing extracellular Mg2+ from normal levels (1.0 mM) to 14% (0.14 mM) did not affect nuclear diameter or silver nitrate reactivity of PHA-stimulated lymphocytes. Chelation of extracellular Ca2+ with EGTA during the first 24 h after PHA stimulation completely inhibited the increases in silver reactivity and nuclear diameter associated with stimulation. Chelation of extracellular Ca2+ 48 h after PHA stimulation did not inhibit lymphocyte stimulation. Inhibitory effects of EGTA were completely reversed if CaCl2 was added to the medium within 24 h of PHA stimulation. By 48 h the effects were irreversible.
D002118:Calcium / Q000494:pharmacology*; D002467:Cell Nucleus / Q000648:ultrastructure; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000648:ultrastructure; D008274:Magnesium / Q000494:pharmacology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*
D010835:Phytohemagglutinins; D004533:Egtazic Acid; D008274:Magnesium; D011188:Potassium; D002118:Calcium