title: Selection of a CXCR4 antagonist from a human heavy chain CDR3-derived phage library.
abstract: Phage display technology is a powerful selection approach to identify strong and specific binders to a large variety of targets. In this study, we compared the efficacy of a phage library displaying human heavy chain complementarity determining region 3 (HCDR3) repertoires with a set of conventional random peptide libraries for the identification of CXCR4 antagonists using a peptide corresponding to the second extracellular loop of the receptor CXCR4 as target. A total of 11 selection campaigns on this target did not result in any specific ligand from the random peptide libraries. In contrast, a single selection campaign with an HCDR3 library derived from the IgM repertoire of a nonimmunized donor resulted in nine specific peptides with lengths ranging from 10 to 19 residues. Four of these HCDR3 sequences interacted with native receptor and the most frequently isolated peptide displayed an affinity of 5.6 μm and acted as a CXCR4 antagonist (IC(50) = 23 μm). To comprehend the basis of the highly efficient HCDR3 library selection, its biochemical properties were investigated. The HCDR3 length varied from 3 to 21 residues and displayed a biased amino acid content with a predominant proportion of Tyr, Gly, Ser and Asp. Repetitive and conserved motifs were observed in the majority of the HCDR3 sequences. The strength and efficacy of the HCDR3 libraries reside in the combination of multiple size peptides and a naturally biased sequence variation. Therefore, HCDR3 libraries represent a powerful and versatile alternative to fully randomized peptide libraries, in particular for difficult targets.
authors.affiliation: Laboratoire de Rétrovirologie, Centre de Recherche Public-Santé, Luxembourg, Luxembourg. andy.chevigne@crp-sante.lu
authors.forename: Andy
authors.initials: A
authors.lastname: Chevigné
authors.forename: Aurélie
authors.initials: A
authors.lastname: Fischer
authors.forename: Julie
authors.initials: J
authors.lastname: Mathu
authors.forename: Manuel
authors.initials: M
authors.lastname: Counson
authors.forename: Nadia
authors.initials: N
authors.lastname: Beaupain
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Plesséria
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Schmit
authors.forename: Sabrina
authors.initials: S
authors.lastname: Deroo
mesh_terms: D000595:Amino Acid Sequence; D022801:Complementarity Determining Regions / Q000737:chemistry; D015723:Gene Library; D006801:Humans; D007075:Immunoglobulin M / Q000737:chemistry; D019151:Peptide Library; D019718:Receptors, CXCR4 / Q000037:antagonists & inhibitors*
chemical_list: C527276:CXCR4 protein, human; D022801:Complementarity Determining Regions; D007075:Immunoglobulin M; D019151:Peptide Library; D019718:Receptors, CXCR4