Mediation of macrophage reactions in immune tissue injury.

The chemotactic specificity of three types of macrophage chemotactic factors (MCF) -a, -b, and -c, from delayed hypersensitivity reaction (DHR) skin sites in guinea pigs, was analysed. MCF-c shared common antigenicity with the macrophage chemotactic lymphokine released from bovine gamma globulin (BGG) and horse radish peroxidase (HRPO) -stimulated lymphocytes, using an immunoadsorbent column conjugated with anti-MCF-c antibody. These purified lymphokines were very similar, or possibly identical in terms of physicochemical and serological properties. BCG-induced lymphokine seemed to exist as complexes with serum protein at the skin site. A change in the proportion of each MCF was observed during the development of DHR. Furthermore, MCF-a and -b attracted Ia- M1 cell line cells, while MCF-c attracted Ia+ cells. Moreover, the responsive guinea-pig monocytes were divided mainly into two distinctive migrating subpopulations. One subpopulation was responsive to MCF-a and -b, and the majority of responding cells were "Ia-negative". The second subpopulation was responsive to MCF-c and the predominant cell type was "Ia-positive". The data suggest that macrophage reactions in the DHR are mediated by MCF-a, -b, and -c and that MCF-c attracts Ia bearing accessory macrophages and MCF-a and b- attract Ia negative macrophages.