title: Role of macrophages in the generation of T helper cells. IV. Nature of genetically related factor derived from macrophages incubated with soluble antigens.
abstract: Macrophages incubated with soluble antigens for 1-4 days release factors capable of inducing T helper cells. The nature and some of the properties of this genetically related macrophage factor (GRF) were investigated. By use of immunoadsorbents, GRF was shown to contain I region-coded products (Ia antigens) linked to a small antigenic fragment. The genes coding for the Ia antigens detectable in GRF lie in the I region of the H-2 complex. GRF does not react with anti-immunoglobulin, anti-C3 or anti-human beta2-microglobulin antisera, and its activity cannot be removed by antigen immunoadsorbents. GRF is heat-labile, sensitive to proteolytic enzymes and has a molecular weight of about 55 000 Daltons. The relationship of GRF to other factors known to contain I region-coded products and reported to be effective in cell cooperation is discussed.
mesh_terms: D000818:Animals; D000941:Antigens; D005796:Genes; D006649:Histocompatibility Antigens; D006358:Hot Temperature; D007164:Immunosorbents; D007519:Isoantigens / Q000032:analysis; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D010206:Papain; D012995:Solubility; D013601:T-Lymphocytes / Q000276:immunology*; D014357:Trypsin
chemical_list: D000941:Antigens; D006649:Histocompatibility Antigens; D007164:Immunosorbents; D007519:Isoantigens; D014357:Trypsin; D010206:Papain