Regulation and proinflammatory properties of the chemotactic protein, CP-10.

Leukocyte recruitment is a central event in the pathogenesis of inflammation and recent studies indicate a variety of factors and chemokines which may be responsible for the temporal changes during the response and determine the cellular composition of the infiltrate [1,2]. We have a long-standing interest in mechanisms involved in accumulation of leukocytes at sites of antigen challenge, particularly in delayed type hypersensitivity (DTH) responses and showed earlier that supernatants of activated murine spleen cells contained a protein of heterogeneous size that caused similar temporal histopathological changes to those typical of antigen-provoked DTH reactions [3]. The purified factor had an apparent molecular mass of 10300 Da and was named chemotactic protein, 10 kDa (CP-10). The partial amino acid sequence indicated that the protein was a member of the S100 family [4]. The cDNA sequence of CP-10 contains an ORF of 267 bp encoding 88 amino acids of calculated mol wt. 10 163 [5]. The protein contains one putative N-glycosylation site but there is no evidence, by mass spectral analysis, of glycosylation of the native protein from a variety of sources. CP-10 cDNA expressed in E. coli [6] or in a mammalian transient transfection system [5] encodes a chemotactic protein. Pure E. coli-derived recombinant CP10 has activity equivalent to the native protein and is chemotactic to human and murine leukocytes.