PGAIPG, a Repeated Hexapeptide of Bovine and Human Tropoelastin, Is Chemotactic for Neutrophils and Lewis Lung Carcinoma Cells

Fetal bovine ligamentum nuchae fibroblasts express a 67-kDa, lactose-sensitive receptor that binds to VGVAPG, a repeated hexapeptide, of bovine and human tropoelastin. Recently, studies utilizing recombinant tropoelastin deletion proteins in conjunction with synthetic peptides identified a second fibroblast receptor binding site, PGAIPG. To evaluate whether PGAIPG is a ligand for elastin receptors of other cells, the chemotactic response of neutrophils and Lewis lung carcinoma tumor cells (M27) was studied. PGAIPG was chemotactic for both of these cells. The maximal response was seen at 10−9 M. VGVAPG desensitized neutrophils to migration induced by PGAIPG confirming that PGAIPG was binding to the 67-kDa receptor. GAIPG, a chemokinetic peptide for fibroblasts, did not induce neutrophil migration. This corroborates the conclusion that GAIPG′s mechanism of action in fibroblasts was independent of the 67-kDa receptor. Unlike fibroblasts and neutrophils, GAIPG was chemotactic for M27 tumor cells.