Fernandez-Medina RD, Lundin K, Berglund M, Wigzell H, Persson MA; International Conference on AIDS.

Int Conf AIDS. 2002 Jul 7-12; 14: abstract no. ThPeA7078.

Karolinska Institute &FIOCRUZ, Stockholm, Sweden

Background A phage display library screening approach was used to identify peptide sequences that could bind to gp13 an anti-HIV-1 Mab that recognises a conformational epitope on the CD4bs of the viral envelope protein gp120. Methods Both a 9 and a 15-mer random phage peptide libraries were used to establish if clones binding to the mentioned antibody could be isolated. The random amino acids residues were constrained by flanking cysteines and fused to the amino terminal end of pIII on the filamentous phage M13. Selection of specific peptides binding to gp13 was done in three rounds of selection with decreasing antibody concentrations after depleting the libraries for clones binding to an irrelevant IgG of the same isotype than gp13. Specific clones were sequenced to determine the amino acid sequences of the binding peptides. Results A Gly-Arg-Trp peptide-motif was found in several of the specific clones isolated from the random libraries. In an attempt to isolate peptides with improved affinity, two new libraries containing the identified amino acid motif GRW flanked by random residues were constructed. After four rounds of selection against Mab gp13 using the new libraries, several new clones were isolated. Two out of five (2/5) sequences from panning three, and 8/16 from panning four, respectively, harboured a consensus sequence RYGRWGPLV. Also, the sequence RRPFFLGRWDPATDL was selected repeatedly both in panning three and four. Binding assays to characterise the binding capacity of these and other clones are being performed. Conclusions Phage display techniques offer an interesting tool for the identification of specific peptides that bind to antibodies. Our preliminary results indicate that we have enriched for sequences and motifs specific for gp13. Binding assays will further elucidate the capacity of gp13 to recognize these clones, and immunisations with positive clones will delineate the capacity for these peptides to act as epitope specific vaccines.

Publication Types:

• Meeting Abstracts

Keywords:

• Antibodies, Monoclonal
• Bacteriophage M13
• Bacteriophages
• Base Sequence
• Epitopes
• Gene Library
• HIV Envelope Protein gp120
• HIV-1
• Peptide Library
• Peptides
• genetics
• immunology

Other ID:

• GWAIDS0013400

UI: 102250898

From Meeting Abstracts