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Peptide mimotopes selected with HIV‐1‐blocking monoclonal antibodies against CCR5 represent motifs specific for HIV‐1 entry
Author(s) -
Königs Christoph,
Pustowka Anette,
Irving James,
Kessel Christoph,
Klich Katharina,
Wegner Valérie,
Rowley Merrill J,
Mackay Ian R,
Kreuz Wolfhart,
Griesinger Christian,
Dietrich Ursula
Publication year - 2007
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1038/sj.icb.7100077
Subject(s) - paratope , epitope , monoclonal antibody , chemokine receptor , biology , peptide , chemokine receptor ccr5 , virology , transfection , phage display , mutant , microbiology and biotechnology , antibody , chemokine , receptor , biochemistry , gene , genetics
CCR5 is a chemokine receptor that mediates entry of human immunodeficiency virus‐1 (HIV‐1). Two monoclonal antibodies (mAbs) that block HIV‐1 entry, 3A9 and 5C7, were used to select peptide mimotopes of sequences on CCR5 from phage displayed peptide libraries. The selected mimotofpes comprised motifs at the N‐terminus and on the first and third extracellular loops (ECL1 and ECL3) of CCR5. Amino acids in these motifs were exchanged for alanines by site‐directed mutagenesis (sdm) in the cDNA for human CCR5. Ensuing effects on antibody binding to CCR5, cellular entry of HIV‐1 and chemokine‐induced signalling were analysed by transfection of mutant cDNAs into HEK293.CD4 cells. For both mAbs, fluorescence‐activated cell sorting analysis was used to define overlapping conformational epitopes on CCR5 at the N‐terminus, on ECL1 and ECL3. Mutation of the N‐terminal motif 10 YD 11 prevented HIV‐1 entry into transfected cells as judged by single round infection assays with R5 and R5X4 HIV‐1 isolates, as did mutation of the motif 96 FG 97 in ECL1, whereas mutation of the motif 274 RLD 276 in ECL3 had only a minor effect. None of the motifs in CCR5 relevant to HIV‐1 entry disrupted chemokine‐induced signalling. Thus, peptide mimotopes of conformational contact sites of CCR5 with the paratope of mAbs 3A9 and 5C7 represent sites on CCR5 that are essential for HIV‐1 entry. Structural knowledge of these mimotopes could help elucidate the nature of the interaction between CCR5 and HIV‐1, and thus the derivation of specific inhibitors of entry of HIV‐1 into susceptible cells without interference with chemokine signalling.