title: Analysis of the fine structure of the antigenic determinants of the transmembrane protein in the HIV coat with chemically modified synthetic peptides.
abstract: The amino acids involved in IgG reactivity to four HIV-1 gp41 overlapping synthetic peptides from the sequence 584-624 have been determined by a method based on the chemical modification of trifunctional amino acids, especially the acetylation of the amino groups of the lysine residues at pH 8-9. The reactivities of the sera from HIV-infected individuals and gp41-specific human Mab were studied with the overlapping peptides and their modified forms in indirect and competitive ELISA. Peptides 584-602 and 609-624 (CN-185) reacted with 88% of HIV-positive sera; the highest diagnostic significance (100%) was found with peptides 584-611 (AS-551) and 603-624 (CN-191). Acetylation resulted in a 10%-15% decrease in peptide reactivity. Moreover the concentration at which 50% inhibition occurred was 1.5 x 10(-6) M for unmodified AS-551 compared with 1.5 x 10(-5) M for the modified peptide. Circular dichroism spectra showed that acetylation did not alter the conformation of these peptides. Coupling of peptide AS-551 to a protein carrier at pH 6.5-7.0 did not affect the immunoreactivity of this peptide. Mab against human gp41 reacted with peptide 603-624 (CN-191). The concentration of this peptide necessary for 50% inhibition of Mab binding was 5.2 x 10(-6) M. It is concluded from the epitope mapping of the Mab that the antigenic determinant lies within the 603-609 fragment. Lys-608 appears to play a crucial role in the interaction with human HIVc-Mab.
authors.affiliation: Institute of Immunology, Ministry of Health of the USSR, Moscow.
authors.forename: S M
authors.initials: SM
authors.lastname: Andreev
authors.forename: D B
authors.initials: DB
authors.lastname: Meshcheryakova
authors.forename: M G
authors.initials: MG
authors.lastname: Vafina
authors.forename: A A
authors.initials: AA
authors.lastname: Az'muko
authors.forename: M V
authors.initials: MV
authors.lastname: Sidorova
authors.forename: R M
authors.initials: RM
authors.lastname: Khaitov
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D015488:HIV Antigens / Q000276:immunology*; D015700:HIV Envelope Protein gp41 / Q000276:immunology*; D016056:Immunodominant Epitopes / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015488:HIV Antigens; D015700:HIV Envelope Protein gp41; D016056:Immunodominant Epitopes; D008565:Membrane Proteins; D010455:Peptides