The specific binding of Listeria monocytogenes-immune T lymphocytes to macrophages. I. Quantitation and role of H-2 gene products.
A system was developed to study the binding of Listeria monocytogenes-specific T cells to L. monocytogenes-pulsed macrophages as an analogue of the initial phase of T-cell activation: antigen recognition. Specific binding, demonstrable after a brief (1 h) contact, was quantitated by the depletion of L. monocytogenes-specific T-cell activity in the cells nonadherent to L. monocytogenes-pulsed macrophage monolayers. L. monocytogenes-specific T-cell function was measured by its ability to activate L. monocytogenes-pulsed macrophages, both to secrete a protein mitogenic for thymocytes and to effect nonspecific tumoricidal activity. These manifestations of T-cell function are known to be regulated by products of I region of the H-2 gene complex. Studies designed to determine the role of H-2 gene products in specific T-cell-macrophage binding have revealed the following. T cells bind specifically to syngeneic macrophages and poorly to allogeneic macrophages. The binding ability appears to map to the K end of the H-2 gene complex (K through I-E). At least two distinct populations of B6AF1 T cells with binding avidity for L. monocytogenes presented on parental macrophages can be identified. Finally, the binding of a given parental-reactive B6AF1 T-cell clone can be specifically inhibited by pretreatment of the antigen-pulsed B6AF1 binding macrophage with anti-H-2 (anti-Ia) antibodies reactive with the appropriate parental haplotype. These results strongly suggest that H-2 gene products play a direct role in mediating the specific binding of T cells to macrophages and imply that the antigen-dependent physical interaction between T cells and macrophages is the initial, and determining, event in some forms of H-2 gene control of immune reactivity.
D000818:Animals; D000942:Antigens, Bacterial; D002450:Cell Communication; D005802:Genes, MHC Class II; D008089:Listeria monocytogenes / Q000276:immunology; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics; D008934:Mitogens / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*
D000942:Antigens, Bacterial; D008934:Mitogens