Characterization of three macrophage chemotactic factors from PPD-induced delayed hypersensitivity reaction sites in guinea pigs, with special reference to a chemotactic lymphokine.

Three types of macrophage chemotactic factors (MCFs) were separated from purified protein derivative (PPD)-induced delayed hypersensitivity (DHR) skin lesions in guinea pigs, and MCF-c was purified isotachophoretically. The macrophage chemotactic activity (MCA) of the skin extract was mostly associated with MCF-a and c. MCF-c (mol wt 110,000) seemed more significant for mediating the macrophage reaction than MCF-a (mol wt 150,000), which exhibited common antigenicity with serum IgG. MCF-b (mol wt 14,000), manifesting common antigenicity with the fifth component of complement (C5), was apparently less significant. MCF-c was thermostable and had an isoelectric point (pI) of 5.2 +/- 0.1. The protein exhibited marked macrophage chemotactic activities (MCA) but no neutrophil chemotactic, lymphocyte chemotactic, and MIF activity in excess of that in vitro. Selective accumulation of macrophages was observed in response to intradermal MCF-c injection. Our studies suggest that MCF-c at 24-hour skin sites of DHR may exist as specific lymphokine preparations with high potential for monocyte infiltration.