title: T-cell-mediated association of peptide antigen and major histocompatibility complex protein detected by energy transfer in an evanescent wave-field.
abstract: Helper T cells recognize foreign antigen displayed on antigenpresenting cells which also express self-molecules of the major histocompatibility complex (MHC). A single T-cell receptor mediates recognition of both MHC and foreign antigen. A proposed ternary complex between T-cell receptor, foreign antigen and MHC antigen has not yet been demonstrated (see ref. 1 for review). Here, we show that a fluorescein-labelled synthetic peptide, together with Texas red-labelled class II MHC antigen, I-Ad, stimulates the production of interleukin-2 by a peptide-specific I-Ad-restricted T-cell hybridoma when reconstituted in a lipid membrane on a glass substrate. Under the same conditions, resonance-energy transfer from donor peptide to acceptor I-A can be stimulated in an evanescent wave-field only in the presence of the specific T-hybrid. Our results show that the T cell stabilizes an association between peptide antigen and class II MHC protein to within a distance of about 40 A.
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D004735:Energy Transfer; D019793:Fluorescein; D005452:Fluoresceins; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006825:Hybridomas; D007376:Interleukin-2 / Q000096:biosynthesis; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D008285:Major Histocompatibility Complex; D051379:Mice; D010047:Ovalbumin / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D005452:Fluoresceins; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D011948:Receptors, Antigen, T-Cell; D010047:Ovalbumin; D019793:Fluorescein