Specific inhibition of HIV-1 coreceptor activity by synthetic peptides corresponding to the predicted extracellular loops of CCR5

• Published in: Blood 2004-02, Vol.103 (4), p.1211-1217
• Main Authors: Agrawal, Lokesh, VanHorn-Ali, Zainab, Berger, Edward A., Alkhatib, Ghalib
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Gene Expression; HeLa Cells; HIV Envelope Protein gp120 - chemistry; HIV Envelope Protein gp120 - genetics; HIV Envelope Protein gp120 - metabolism; HIV Infections - metabolism; HIV-1; Human viral diseases; Humans; Infectious diseases; Medical sciences; Membrane Fusion; Mice; NIH 3T3 Cells; Peptide Fragments - genetics; Peptide Fragments - metabolism; Peptide Fragments - pharmacology; Peptide Mapping; Protein Structure, Tertiary; Radioligand Assay; Receptors, CCR5 - chemistry; Receptors, CCR5 - genetics; Receptors, CCR5 - metabolism; Structure-Activity Relationship; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2003-08-2669

We used synthetic peptides to the extracellular loops (ECLs) of CCR5 to examine inhibitory effects on HIV infection/fusion with primary leukocytes and cells expressing recombinant CCR5. We show for the first time that peptides derived from the first, second, or third ECL caused dose-dependent inhibition of fusion and infection, although with varying potencies and specificities for envelope glycoproteins (Envs) from different strains. The first and third ECL peptides inhibited Envs from the R5 Ba-L strain and the R5X4 89.6 strain, whereas the second ECL peptide inhibited Ba-L but not 89.6 Env. None of the peptides affected fusion mediated by Env from the X4 LAV strain. Fusion mediated by Envs from several primary HIV-1 isolates was also inhibited by the peptides. These findings suggest that various HIV-1 strains use CCR5 domains in different ways. Experiments involving peptide pretreatment and washing, modulation of the expression levels of Env and CCR5, analysis of CCR5 peptide effects against different coreceptors, and inhibition of radiolabeled glycoprotein (gp) 120 binding to CCR5 suggested that the peptide-blocking activities reflect their interactions with gp120. The CCR5-derived ECL peptides thus provide a useful approach to analyze structure–function relationships involved in HIV-1 Env-coreceptor interactions and may have implications for the design of drugs that inhibit HIV infection.