Calalb M B, Stanton T H, Smith L, Cragoe E J, Bomsztyk K
J Biol Chem. 1987 Mar 15;262(8):3680-4.
Interleukin-1 a polypeptide hormone produced by activated macrophages is a mixture of at least two proteins, interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta). We have previously shown that macrophage-derived interleukin-1 induced new kappa light chain synthesis for surface IgM expression in a murine pre-B like cell line 70Z/3, a finding associated with an early amiloride-sensitive rise in the total intracellular sodium concentration. Because IL-1 alpha and IL-1 beta are structurally quite different, in this study their effect on 70Z/3 was examined separately. The results show that both human rIL-1 alpha and rIL-1 beta induce the differentiation of 70Z/3, but a higher concentration of rIL-1 beta compared to rIL-1 alpha is needed for a maximal response. At saturating concentrations, both rIL-1 alpha and rIL-1 beta induce a simultaneous rise in intracellular pH and sodium concentration. Because rIL-1 mediated intracellular alkalinization and sodium rise are amiloride sensitive, they likely occur through stimulation of the Na+/H+ exchanger across the cell membrane. Inhibition of the Na+/H+ antiport with an amiloride analog did not have an effect on rIL-1 induced surface IgM expression or the rIL-1-mediated increase in kappa light chain specific mRNA level. Therefore, these results indicate that an increase in pHi or [Na]i is not required for IL-1 induced 70Z/3 differentiation.
白细胞介素-1是一种由活化巨噬细胞产生的多肽激素，是至少两种蛋白质的混合物，即白细胞介素-1α（IL-1α）和白细胞介素-1β（IL-1β）。我们先前已表明，巨噬细胞衍生的白细胞介素-1可诱导鼠前B样细胞系70Z/3合成新的κ轻链以表达表面IgM，这一发现与细胞内总钠浓度早期对氨氯地平敏感的升高有关。由于IL-1α和IL-1β在结构上有很大差异，本研究分别检测了它们对70Z/3的作用。结果表明，人重组IL-1α和重组IL-1β均可诱导70Z/3分化，但与重组IL-1α相比，需要更高浓度的重组IL-1β才能产生最大反应。在饱和浓度下，重组IL-1α和重组IL-1β均可诱导细胞内pH值和钠浓度同时升高。由于重组IL-1介导的细胞内碱化和钠升高对氨氯地平敏感，它们可能是通过刺激细胞膜上的Na+/H+交换体而发生的。用氨氯地平类似物抑制Na+/H+反向转运对重组IL-1诱导的表面IgM表达或重组IL-1介导的κ轻链特异性mRNA水平升高没有影响。因此，这些结果表明，IL-1诱导70Z/3分化不需要细胞内pH值或[Na]i升高。
