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 antiboby. 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 subpopula‐tion was responsive to MCF‐a and ‐b, and the majority of responding cells were “la‐negative“. The second subpopulation was responsive to MCF‐c and the predominant cell type was “la‐positive”. The data suggest that macrophage reactions in the DHR are mediated by MCF‐a, ‐b, and ‐c and that MCF‐c attracts la bearing accessory macrophages and MCF‐a and b‐ attract la negative macrophages. ACTA PATHOL. JPN. 35 : 269–280, 1985.