title: Growth regulation of transformed T cells by nonactivated macrophages: the role of Ia expression.
abstract: We studied the influence of unactivated mouse peritoneal macrophages on the proliferative capacity of a spontaneously transformed MRL-lpr/lpr T cell clone. Macrophages, 25%, induced a reduction in proliferative rate from 20% to 95% measured by [3H]thymidine incorporation and microscopic cytometry. MHC-compatible (H-2k) macrophages caused growth inhibition reciprocal to the amount of Ia expression on the macrophage. Thus, with increasing preculture of the macrophages there was both decreasing Ia and increasing suppression. H-2-incompatible macrophages had maximal inhibitory capacity without preincubation. Macrophages derived from the peritoneum of MRL-lpr/lpr mice were less suppressive than macrophages from other H-2k mice. In contrast to the case of activated macrophages in other studies, in the present system there was no killing of T cells, only reduction in proliferation. The inhibitory effect of the macrophages correlated with the spontaneous formation of rosettes between the macrophages and the T cell clone. The number of rosettes forming a single layer of T cells around the macrophages, but not the number of rosettes with multiple layers of cells, was reciprocally related to the amount of Ia expression. The results suggest that macrophages bear a surface structure that influences and modulates the growth of T cells.
mesh_terms: D000818:Animals; D002450:Cell Communication; D002455:Cell Division; D002999:Clone Cells / Q000166:cytology / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000276:immunology*; D007106:Immune Sera / Q000494:pharmacology; D008213:Lymphocyte Activation; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000502:physiology
chemical_list: D000949:Histocompatibility Antigens Class II; D007106:Immune Sera