title: Functional heterogeneity of culture-grown bone marrow-derived macrophages. II. Lymphokine stimulation of antigen-presenting function.
abstract: The activation of immunostimulatory activity and Ia expression was studied in pure populations of murine macrophages (M phi) grown in vitro from bone marrow precursor cells in the presence of L cell-conditioned medium as the source of colony-stimulating factor. During exponential growth, the M phi developed maximal Ia-dependent antigen-presenting activity as detected by the induction of antigen-specific T cell proliferation, but the proportion of Ia+ M phi was low (less than 10%). Fractionation of the M phi according to size by velocity sedimentation resulted in concentration of the antigen-presenting cells in the smallest fraction, but the enrichment of Ia+ M phi in this fraction was less than twofold. All fractions also showed comparable degrees of antigen uptake regardless of their T cell-stimulating activity. Thus Ia and antigen, although obviously essential, are insufficient for full manifestation of antigen-presenting function. Activation of M phi with lymphokines from Mycobacterium-activated lymph node cells resulted in enhanced Ia expression in all fractions, but only small M phi showed an enhancement in antigen presentation. Large activation M phi were found to exert an immunosuppressive effect that probably neutralized any augmentation of stimulatory activity. thus heterogeneity can be demonstrated in i) the function of unstimulated M phi, ii) the responsiveness of subsets to stimulation, and iii) the manifestation of activated functions.
mesh_terms: D000818:Animals; D015478:Antigens, Heterophile / Q000276:immunology*; D001854:Bone Marrow Cells; D002469:Cell Separation; D002478:Cells, Cultured; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015478:Antigens, Heterophile; D000949:Histocompatibility Antigens Class II; D008222:Lymphokines