Contribution of cytokine-induced neutrophil chemoattractant CINC-2 and CINC-3 to neutrophil recruitment in lipopolysaccharide-induced inflammation in rats

Objective: We have estimated the contribution of three types of cytokine-induced neutrophil chemoattractants (CINC-1, -2 and -3) and rat macrophage inflammatory protein (MIP)-1 alpha to neutrophil recruitment in the air pouch/lipopolysaccharide (LPS)-induced inflammation in rats. Materials and methods: Excess amounts of anti-CINC-2, CINC-3 and MIP-1 alpha antibodies (Abs), together with LPS (1 mug/ml), were injected into the preformed air pouch of rats. Chemokine levels and chemotactic activity in the pouch fluid were measured using enzyme-linked immunosorbent assay and multiwell-type Boyden chambers in vitro, respectively. Results: Excess amounts of the Abs significantly neutralized CINC-1 and almost completely neutralized CINC-2, CINC-3 and MIP-1 alpha in the pouch fluid, and a significant suppression (about 60% inhibition) of neutrophil infiltration by the Abs was found. In agreement with the in vivo results, in vitro neutralization experiments demonstrated that complete neutralization of CINCs and MIP-1 alpha by the Abs resulted in a marked suppression (73% inhibition) of chemotactic potency of 8-h pouch fluid (exudate) from LPS-treated rats. On the other hand, treatment with anti-CINC-2, CINC-3 or MIP-1 alpha Ab alone resulted in 48%, 34% or 10% inhibition respectively, of chemotactic activity of the 8-h exudate. Conclusions: Our results suggest that CINC-2, a novel rat CXC chemokine and CINC-3 play an important role in neutrophil recruitment in the rat air pouch/LPS-induced inflammation.