Changes of intracellular IP3 with the expression of interleukin 2 receptor in human peripheral blood T lymphocytes.

The changes of the intracellular inositol-1,4,5-triphosphate (IP3) associated with the expression of the interleukin 2 receptor (IL-2R) were studied. In resting lymphocytes, IL-2 did not alter intracellular concentration of IP3, but Con A caused an increase in IP3 by 45%. In IL-2 sensitive T cells, which expressed IL-2R by 83%, the change of intracellular IP3 was dependent upon IL-2 concentration. The IP3 increased at IL-2 concentrations of 10 and 50 U/ml, and the maximal response of 60% was found at the concentration of 50 U/ml. At IL-2 concentration of 100 U/ml no increase in IP3 was observed. After binding of anti-Tac McAb to IL-2R of T lymphocytes the increase in IP3 at IL-2 concentrations of 10 and 50 U/ml was significantly attenuated. It has been suggested that IL-2 could induce the changes of intracellular IP3 of the human peripheral blood T cells, which is related to the IL-2 concentrations incubated with T cells and the expression of IL-2R on T lymphocyte.