title: Determination of the relationship between T cell responsiveness and the number of MHC-peptide complexes using specific monoclonal antibodies.
abstract: We describe the generation of three mAbs that recognize the complex of the class II MHC molecule IEk bound to a peptide derived from the carboxyl terminus of moth cytochrome c (residues 95-103). Reactivities of these mAbs are sensitive to single alterations in the sequence of both helices of the MHC molecule and to the bound peptide. The epitopes of these reagents are distinct but overlap substantially. One of these mAbs specifically blocks lymphokine release by T cells responsive to this complex but not others. We have used another to examine how the number of complexes on an APC is related to its ability to stimulate T cells. We find that 200-400 complexes per cell are necessary and sufficient to induce a degree of stimulation, whereas maximum stimulation is achieved only if more than 5000 complexes are present. The analysis indicates that T cell activation is a stochastic process.
authors.affiliation: Howard Hughes Medical Institute and Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA. preay@worf.molbiol.ox.ac.uk
authors.forename: P A
authors.initials: PA
authors.lastname: Reay
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: K
authors.initials: K
authors.lastname: Haase
authors.forename: C
authors.initials: C
authors.lastname: Wulfing
authors.forename: Y H
authors.initials: YH
authors.lastname: Chien
authors.forename: M M
authors.initials: MM
authors.lastname: Davis
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000378:metabolism; D000915:Antibody Affinity; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D001667:Binding, Competitive / Q000276:immunology; D002460:Cell Line; D003574:Cytochrome c Group / Q000276:immunology / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000276:immunology* / Q000378:metabolism; D006825:Hybridomas; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009036:Moths; D010446:Peptide Fragments / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D003574:Cytochrome c Group; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen; D007140:Immunoglobulin Fab Fragments; D010446:Peptide Fragments