title: Copresentation of natural HIV-1 agonist and antagonist ligands fails to induce the T cell receptor signaling cascade.
abstract: It is not known how human immunodeficiency virus type 1 (HIV-1)-derived antagonist peptides interfere with intracellular activation of cytotoxic T lymphocytes (CTL). We identified Gag epitope variants in HIV-1-infected patients that act as antagonists of CTL responses to unmutated epitopes. We then investigated the effect that presentation of each variant has on the early events of T cell receptor (TCR) signal transduction. We found that altered peptide ligands (APL) failed to induce phosphorylation of pp36, a crucial adaptor protein involved in TCR signal transduction. We further investigated the effect that simultaneous presentation of APL and native antigen at low, physiological, peptide concentrations (1 nM) has on TCR signal transduction, and we found that the presence of APL can completely inhibit induction of the protein tyrosine phosphorylation events of the TCR signal transduction cascade.
authors.affiliation: University of Oxford, Nuffield Department of Medicine and Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom.
authors.forename: M A
authors.initials: MA
authors.lastname: Purbhoo
authors.forename: A K
authors.initials: AK
authors.lastname: Sewell
authors.forename: P
authors.initials: P
authors.lastname: Klenerman
authors.forename: P J
authors.initials: PJ
authors.lastname: Goulder
authors.forename: K L
authors.initials: KL
authors.lastname: Hilyard
authors.forename: J I
authors.initials: JI
authors.lastname: Bell
authors.forename: B K
authors.initials: BK
authors.lastname: Jakobsen
authors.forename: R E
authors.initials: RE
authors.lastname: Phillips
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000595:Amino Acid Sequence; D000938:Antigen-Presenting Cells / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D015683:Gene Products, gag / Q000737:chemistry / Q000276:immunology*; D014644:Genetic Variation; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D015398:Signal Transduction; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000821:virology
chemical_list: D000939:Epitopes; D015683:Gene Products, gag; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins