The peritoneal antigen-presenting macrophage: control and immunogenic properties of distinct subpopulations.

The control of the immunogenic antigen-presenting capacity of different subpopulations of thioglycollate-induced peritoneal macrophages had been investigated. The experiments revealed the existence of two major subpopulations of macrophages, only one of which was highly efficient in educating antigen-specific T cells. The other subpopulation, while highly phagocytic, was devoid of antigen-presenting capacity. Further analysis, using specific antisera directed at H-2I region gene products, revealed that the immunogenic antigen-presenting population expressed H-2I region-controlled membrane antigens. Searching for cellular elements which control the differentiation of this antigen-presenting macrophage subpopulation, it was found that its function was strictly controlled by T cells. T cell-deficient mice (nu/nu) failed to generate a functional antigen-presenting macrophage subpopulation. Transplantation of mature T lymphocytes to T cell-deprived mice restored the immunogenic function of their antigen-presenting macrophage subpopulation. Transplantation of mature T lymphocytes to T cell-deprived mice restored the immunogenic function of their antigen-presenting macrophages. The results obtained suggest the existence of heterogeneity of functions among macrophage subpopulations and add a new regulatory function for T cells.