title: Interaction between the CD8 coreceptor and major histocompatibility complex class I stabilizes T cell receptor-antigen complexes at the cell surface.
abstract: The off-rate (k(off)) of the T cell receptor (TCR)/peptide-major histocompatibility complex class I (pMHCI) interaction, and hence its half-life, is the principal kinetic feature that determines the biological outcome of TCR ligation. However, it is unclear whether the CD8 coreceptor, which binds pMHCI at a distinct site, influences this parameter. Although biophysical studies with soluble proteins show that TCR and CD8 do not bind cooperatively to pMHCI, accumulating evidence suggests that TCR associates with CD8 on the T cell surface. Here, we titrated and quantified the contribution of CD8 to TCR/pMHCI dissociation in membrane-constrained interactions using a panel of engineered pMHCI mutants that retain faithful TCR interactions but exhibit a spectrum of affinities for CD8 of >1,000-fold. Data modeling generates a "stabilization factor" that preferentially increases the predicted TCR triggering rate for low affinity pMHCI ligands, thereby suggesting an important role for CD8 in the phenomenon of T cell cross-reactivity.
authors.affiliation: T Cell Modulation Group, Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, South Parks Road, Oxford OX1 3SY, United Kingdom.
authors.forename: Linda
authors.initials: L
authors.lastname: Wooldridge
authors.forename: Hugo A
authors.initials: HA
authors.lastname: van den Berg
authors.forename: Meir
authors.initials: M
authors.lastname: Glick
authors.forename: Emma
authors.initials: E
authors.lastname: Gostick
authors.forename: Bruno
authors.initials: B
authors.lastname: Laugel
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Hutchinson
authors.forename: Anita
authors.initials: A
authors.lastname: Milicic
authors.forename: Jason M
authors.initials: JM
authors.lastname: Brenchley
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Douek
authors.forename: David A
authors.initials: DA
authors.lastname: Price
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Sewell
mesh_terms: D000941:Antigens / Q000737:chemistry; D001703:Biophysics / Q000379:methods; D019921:Biotinylation; D016827:CD8 Antigens / Q000096:biosynthesis / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D000939:Epitopes / Q000737:chemistry; D005434:Flow Cytometry; D005805:Genes, MHC Class I / Q000235:genetics*; D005818:Genetic Engineering; D015497:HIV-1 / Q000378:metabolism; D004854:Herpesvirus 4, Human / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008956:Models, Chemical; D009154:Mutation; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors
chemical_list: D000941:Antigens; D016827:CD8 Antigens; C067361:CD8 receptor; D000939:Epitopes; D008024:Ligands; D011948:Receptors, Antigen, T-Cell