EVIDENCE FOR 2 PUTATIVE RECEPTORS MEDIATING CHEMOTACTIC ACTIVITY OF CYTOKINE-INDUCED NEUTROPHIL CHEMOATTRACTANTS (CINCS) FOR RAT NEUTROPHILS

Recently we have found that only cytokine-induced neutrophil chemoattr actant (CINC)-3 induces an increase in intracellular [Ca2+] in rat neu trophils stimulated first with CINC-1, CINC-2 alpha or CINC-2 beta, an d hypothesized that rat neutrophils have another receptor specific for CINC-3 in addition to a common receptor for all CINCs [Shibata P., et al., Eur. J. Biochem., 231, 306 (1995)]. To evaluate this hypothesis, chemotactic activity of these CINCs ill vitro was determined by using rat neutrophils together with each CINC. In the presence of CINC-1, m igration of neutrophils toward CINC-1, CINC-2 alpha and CINC-2 beta wa s inhibited, but that toward CINC-3 was not. Similar results were obta ined when CINC-2 alpha or CINC-2 beta was added to neutrophils. Howeve r, addition of CINC-3 to neutrophil suspension in the upper chamber re sulted in the complete inhibition of the neutrophil migration toward e ach CINC. The results support our hypothesis and indicate both the put ative receptors can mediate chemotaxis of rat neutrophils.