title: Partially modified retro-inverso pseudopeptides as non-natural ligands for the human class I histocompatibility molecule HLA-A2.
abstract: Syntheses of a series of partially modified retro-inverso analogues of the antigenic peptide M58-66 derived from the influenza virus matrix protein are reported. The retro-inverso modification phi(NH-CO) was obtained by replacement of two successive amino acid residues with a 2-substituted malonate derivative and gem-diaminoalkyl residue. The resulting compounds 1-8 were tested for their binding to the human histocompatibility class I molecule HLA-A2 in an assembly assay using lysates of peptide transporter-deficient cells T2. Specific peptide-dependent HLA-A2 assembly was revealed by an enzyme-linked immunosorbent assay. Significant HLA-A2 assembly was detected in the presence of analogues [gGly58-(S)mLeu59]-M58-66 (1a), [gGly61-(R,S)mPhe62]M58-66 (4), [gVal63-(R,S)mPhe64]M58-66 (6), and [gPhe64-(R,S)mAla65]M58-66 (7). The introduction of the retro-inverso modification between P2-P3, P3-P4, P5-P6, and P8-P9 (compounds 2, 3, 5, and 8, respectively) however led to a dramatic reduction in peptide binding to HLA-A2. Interestingly, compound 1a which contains modification between P1-P2 was found to be the most potent analogue, being able to retain the original HLA-A2 binding profile of the parent peptide M58-66. Taken together, these results and recent binding data obtained in the context of murine MHC class I molecule H-2Kd suggest that the incorporation of peptide bond surrogates in MHC class I-restricted epitopes is a useful approach to design molecules having both increased stability and high MHC-binding capacity. Depending on their agonist or antagonist effects at the T-cell receptor, such non-natural MHC ligands are likely to find many applications in the development of peptide-based vaccines or as potential therapeutic agents in the treatment of allergies and autoimmune diseases.
authors.affiliation: Institut de Biologie Moléculaire et Cellulaire, UPR 9021 CNRS, Strasbourg, France.
authors.forename: G
authors.initials: G
authors.lastname: Guichard
authors.forename: F
authors.initials: F
authors.lastname: Connan
authors.forename: R
authors.initials: R
authors.lastname: Graff
authors.forename: M
authors.initials: M
authors.lastname: Ostankovitch
authors.forename: S
authors.initials: S
authors.lastname: Muller
authors.forename: J G
authors.initials: JG
authors.lastname: Guillet
authors.forename: J
authors.initials: J
authors.lastname: Choppin
authors.forename: J P
authors.initials: JP
authors.lastname: Briand
mesh_terms: D000595:Amino Acid Sequence; D015789:HLA-A2 Antigen / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D008969:Molecular Sequence Data; D009975:Orthomyxoviridae / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014407:Tumor Cells, Cultured; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015789:HLA-A2 Antigen; D008024:Ligands; D010455:Peptides; D014763:Viral Matrix Proteins