Calcium ion influx during mitogenic stimulation of lymphocytes.

Abstract

ABSTRACT. The uptake of free calcium ion (Ca2+) in PHA-or A23187-stimulated lymphocytes was measured using 45CaCl2 and 3H-water.

Lymphocyte calmodulin and its participation in the stimulation of T lymphocytes by mitogenic lectins

“…The uptake of Ca 2+ by lymphocytes was determined with 45CACI2 (New England Nuclear, Boston, MA) and 3H-water (New England Nuclear, Boston, MA) by the method of centrifugation of cells through an oil layer (dim-butyl phthalate : corn oil = 100:33) as described previously [18,19]. Briefly, lymphocytes were incubated at 37°C for 30 min in the culture medium supplemented wiht l0 ¢Ci of 45CaCIz (24.5 mCi/mg) or 100 ~Ci ~H-water (100 mCi/mg), l 106 ceils in l ml of the medium were layered on 0.5 ml of oil layer in a polypropylene microcentrifuge tube, and centrifuged at 8 500 rpm for 2 min.…”

“…These concentrations of the drugs were selected for the measurement of 45Ca2+ uptake. The effect of TFP on 45Ca 2÷ uptake was determined after 30 min of mitogen and/or TFP addition, because the augmentation of Ca 2÷ uptake due to mitogenic lectins was transient occurring within 30 min [19], and because calmodulin antagonists were effective in an early phase of stimulation [3,8]. Mitogenic doses of PHA and ConA enhanced Ca 2÷ uptake by lymphocytes to about• 1.3-and 1.6-fold, respectively ( fig 5).…”

“…Evidence has accumulated for the pivotal role of calcium ions (Ca 2+) in lymphocyte stimulation: 1) extracellular Ca 2÷ is essential for the mitogenesis [1,19] ; 2) mitogenic lectins induce early increase both in 45Ca2+ uptake [12,19] and in cytoplasmic free calcium ion concentration [13,19,20,37,38]; and 3) Ca2+-ionophore A23187 [23,24] and ionomycin [20] have a mitogenic potency, while calciumchannel blockers inhibit lectin-induced stimulation [4,5,26,27].…”

Measurement of the cytosolic free calcium ion concentration of individual lymphocytes by microfluorometry using quin 2 or fura-2.

“…We reported the enhancement of Ca2+ uptake and the rise in the [Ca2+]i in the initial step of stimulation, but these events occurred transiently (7). The role of the augmentation of Ca2+ uptake and of the [Ca2+]i, and the necessity of Ca2+ have been discussed by many researchers (2,3,6,7,10,16).…”

Mobiloization of intracellular calcium ions in chicken and rat lymphocytes induced by T cell mitogens

“…Cytosolic Ca 2+ is an important factor in cellular signal transduction pathways (Samelson 2002). In mammalian T lymphocytes, the contribution that the mobilization of cytosolic Ca 2+ makes during the mitogen-induced activation of cells has been well established (Komada et al 1987;Mueller et al 1990). An elevation in the intracellular concentration of Ca 2+ ([Ca 2+ ]i) induced by ConA has been reported to trigger the expression of the interleukin-2 (IL-2) receptor and production of IL-2 in human lymphocytes (Komada et al 1996).…”