Recombinant human interleukin 1-stimulated Na+/H+ exchange is not required for differentiation in pre-B lymphocyte cell line, 70Z/3.
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.
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D011994:Recombinant Proteins / Q000494:pharmacology*; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D007375:Interleukin-1; D011994:Recombinant Proteins; D017923:Sodium-Hydrogen Exchangers