title: The minimal number of class II MHC-antigen complexes needed for T cell activation.
abstract: Major histocompatibility complex (MHC) molecules are exposed to large quantities of self and nonself antigens. It is not known what fraction of MHC molecules needs to be occupied by antigen to induce a T cell response. A quantitative study of naturally processed antigen indicated that T cells could be activated when only 0.03 percent of the total I-Ed purified from antigen-presenting cells (APCs) was occupied with antigen. B cells and macrophages processed hen egg lysozyme (HEL) with different efficiencies, but similar degrees of occupancy were required for T cell stimulation. Higher occupancy was needed for I-Ed-transfected L cells, possibly reflecting the requirement for other accessory molecules for efficient APC-T cell interaction.
authors.affiliation: Cytel Corporation, La Jolla, CA 92037.
authors.forename: S
authors.initials: S
authors.lastname: Demotz
authors.forename: H M
authors.initials: HM
authors.lastname: Grey
authors.forename: A
authors.initials: A
authors.lastname: Sette
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007700:Kinetics; D008213:Lymphocyte Activation; D008223:Lymphoma; D008264:Macrophages / Q000276:immunology; D009113:Muramidase / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection
chemical_list: D000949:Histocompatibility Antigens Class II; D009113:Muramidase