THE EFFECT OF L-GLUTAMIC ACID ON THE RECE PTION OF CYTOKINES BY HL-60CELLS

L-Glutamic acid at a concentration of 0.1 mu M was found to induce dif ferentiation of the cell line of HL-60 promyelocytic leukemia into gra nulocytes or neutrophiles. The HL-60 cells have no specific glutamate- binding sites, but L-glutamic acid influences the reception of several cytokines by these cells. At a concentration of 0.1 mu M, L-glutamic acid completely inhibits the high-affinity binding of I-125-labeled hu man recombinant interleukin-1 beta (K-d = 0.32 nM) to the HL-60 cells, but does not affect their low-affinity binding (K-d = 13.3 nM) and do es not change the total number of the IL-1 beta-binding sites. Preincu bation of the HL-60 cells with 0.1 mu M of L-glutamic acid increases 2 .5 times the number of receptors for I-125-labeled human recombinant t umor necrosis factor beta. These results suggest that L-glutamic acid plays an important role in the differentiation of the blood myeloid ce lls.