Evidence for two putative receptors mediating chemotactic activity of cytokine-induced neutrophil chemoattractants (CINCs) for rat neutrophils.

Recently we have found that only cytokine-induced neutrophil chemoattractant (CINC)-3 induces an increase in intracellular [Ca2+] in rat neutrophils stimulated first with CINC-1, CINC-2 alpha or CINC-2 beta, and hypothesized that rat neutrophils have another receptor specific for CINC-3 in addition to a common receptor for all CINCs [Shibata F., et al., Eur. J. Biochem., 231, 306 (1995)]. To evaluate this hypothesis, chemotactic activity of these CINCs in vitro was determined by using rat neutrophils together with each CINC. In the presence of CINC-1, migration of neutrophils toward CINC-1, CINC-2 alpha and CINC-2 beta was inhibited, but that toward CINC-3 was not. Similar results were obtained when CINC-2 alpha or CINC-2 beta was added to neutrophils. However, addition of CINC-3 to neutrophil suspension in the upper chamber resulted in the complete inhibition of the neutrophil migration toward each CINC. The results support our hypothesis and indicate both the putative receptors can mediate chemotaxis of rat neutrophils.