title: The effects of changes at peptide residues contacting MHC class II T-cell receptor on antigen recognition and human Th0 cell effector function.
abstract: Cytokines can influence the selection of functional subsets (Th1 or Th2) of CD4+ T cells. However, quantitative changes in affinity of peptide/major histocompatibility complex (MHC) class II/T-cell receptor (TCR) interactions may alter antigen density and modulate T-cell effector function. The possibility exists to use peptide analogues to induce a partial signal to dissociate production of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) by T-helper type-0 (Th0) cells and, consequently, to regulate T-cell function. Based on binding assays and resolution of the crystalline structure of an influenza virus haemagglutinin peptide (HA 306-318) bound to the human MHC class II molecule DRB1*0101, we synthesized HA peptide analogues with amino acid substitutions predicted to modify either MHC class II/peptide density or TCR/peptide interactions. When we examined their antigenicity using cloned human Th0 cells, the analogues, in general, elicited a gradation in potency reflected by a reduction in both proliferation and cytokine production (IL-2, IL-4 and IFN-gamma). Although the analogue HA-R309 diminished IL-2 production, none of the analogues tested could selectively induce only IL-4 or IFN-gamma. Since, in general, the effector functions of the Th0 cells examined here were resistant to selective manipulation by the peptide analogues, this suggests that for some clones of chronically activated T cells modulation of selected functions may be difficult to achieve.
authors.affiliation: Department of Biology, Imperial College of Science, Technology and Medicine, London, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Lamb
authors.forename: J A
authors.initials: JA
authors.lastname: Higgins
authors.forename: C
authors.initials: C
authors.lastname: Hetzel
authors.forename: J D
authors.initials: JD
authors.lastname: Hayball
authors.forename: R A
authors.initials: RA
authors.lastname: Lake
authors.forename: R E
authors.initials: RE
authors.lastname: O'Hehir
mesh_terms: D000595:Amino Acid Sequence; D002455:Cell Division / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000737:chemistry / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D015847:Interleukin-4 / Q000276:immunology; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D011994:Recombinant Proteins; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D016207:Cytokines; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D000949:Histocompatibility Antigens Class II; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; C086595:influenza hemagglutinin (306-318); D015847:Interleukin-4; D007371:Interferon-gamma