Use of Blocking Antibodies as Probes for in Vivo Functions of Chemokines

Leukocyte infiltration into an inflammatory site is one of the pathological hallmarks of inflammatory reaction. Locally produced chemotactic factors are presumed to mediate the sequence of events leading to tissue injury associated with the infiltration of leukocytes. Chemotactic cytokines (chemokines) have been identified as being produced by various types of cells upon stimulation with inflammatory stimuli and exhibit a variety of effects on leukocytes in vitro and in vivo. Administration of highly specific neutralizing antibodies against these chemokines in several types of animal inflammation models clearly suggests important roles of these chemokines in recruiting and activating specific types of leukocytes at the inflammatory sites. Anti-IL-8 Ab treatment prevented neutrophil-dependent tissue damage as well as neutrophil infiltration in lipopolysaccharide (LPS)-induced dermatitis, LPS/IL-1-induced arthritis, lung reperfusion injury, and acute immune complex type glomerulonephritis in rabbits. Moreover, anti-MCP-1 Ab and anti-RANTES Ab inhibited macrophage infiltration in IgA immune complex alveolitis in rats and influx of lung macrophages in a murine model of endotoxemia, respectively. The use of anti-MIP-1alpha Ab also revealed that MIP-1alpha mediates eosinophil infiltration in allergic, granulomatous reactions in vivo.