Influence of l-glutamic acid on binding of interleukin-1 β, tumour necrosis factor- α and interleukin-6 to HL-60 cells

To elucidate the mechanism of differentiating activity on l-Glu to HL-60 cells, its influence on binding of human recombinant interleukine-1 β (rHuIL-l β), tumour necrosis factor- α (rHuTNF- α) and interleukine-6 (IL-6) by HL-60 cells was studied. It was established, that l-Glu converted the high affinity binding of [ 125I]rHuIL-l β ( K d=0.32 nM) and [ 125I]rHuIL-6 ( K d=0.075 nM) to HL-60 cells into low affinity (corresponding K d values −13.3 and 2.1 nM) at concentration 0.1 μM. The preincubation for an hour of HL-60 cells with 0.1 μM l-Glu was shown to result in an increase of affinity and number of [ 125I]rHuTNF- α binding sites. Thus, l-Glu decreases the sensitivity of the HL-60 cells to IL-1 β and IL-6 and increases TNF- α binding at concentration 0.1 μM.