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Journal of Virology, December 2009, p. 12151-12163, Vol. 83, No. 23
0022-538X/09/$08.00+0     doi:10.1128/JVI.01351-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Structure-Function Analysis of Human Immunodeficiency Virus Type 1 gp120 Amino Acid Mutations Associated with Resistance to the CCR5 Coreceptor Antagonist Vicriviroc ^,

Robert A. Ogert,¹ Lei Ba,¹ Yan Hou,¹ Catherine Buontempo,¹ Ping Qiu,² Jose Duca,³ Nicholas Murgolo,² Peter Buontempo,¹ Robert Ralston,¹ and John A. Howe^1*

Departments of Biological Sciences-Virology,¹ Molecular Design and Informatics,² Drug Design, Schering-Plough Research Institute, 2015 Galloping Hill Road, K-15-4945, Kenilworth, New Jersey 07033³

Received 1 July 2009/ Accepted 14 September 2009

Vicriviroc (VCV) is a small-molecule CCR5 coreceptor antagonist currently in clinical trials for treatment of R5-tropic human immunodeficiency virus type 1 (HIV-1) infection. With this drug in development, identification of resistance mechanisms to VCV is needed to allow optimal outcomes in clinical practice. In this study we further characterized VCV resistance in a lab-adapted, VCV-resistant RU570 virus (RU570-VCV_res). We show that K305R, R315Q, and K319T amino acid changes in the V3 loop, along with P437S in C4, completely reproduced the resistance phenotype in a chimeric ADA envelope containing the C2-V5 region from RU570 passage control gp120. The K305R amino acid change primarily impacted the degree of resistance, whereas K319T contributed to both resistance and virus infectivity. The P437S mutation in C4 had more influence on the relative degree of virus infectivity, while the R315Q mutation contributed to the virus concentration-dependent phenotypic resistance pattern observed for RU570-VCV_res. RU570-VCV_res pseudovirus entry with VCV-bound CCR5 was dramatically reduced by Y10A, D11A, Y14A, and Y15A mutations in the N terminus of CCR5, whereas these mutations had less impact on entry in the absence of VCV. Notably, an additional Q315E/I317F substitution in the crown region of the V3 loop enhanced resistance to VCV, resulting in a stronger dependence on the N terminus for viral entry. By fitting the envelope mutations to a molecular model of a recently described docked N-terminal CCR5 peptide consisting of residues 2 to 15 in complex with HIV-1 gp120 CD4, potential new interactions in gp120 with the N terminus of CCR5 were uncovered. The cumulative results of this study suggest that as the RU570 VCV-resistant virus adapted to use the drug-bound receptor, it also developed an increased reliance on the N terminus of CCR5.

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* Corresponding author. Mailing address: Schering-Plough Research Institute, 2015 Galloping Hill Road, K-15-E403C, MS 4945, Kenilworth, NJ 07033. Phone: (908) 740-7260. Fax: (908) 740-3032. E-mail: john.howe{at}spcorp.com

Published ahead of print on 23 September 2009.

The authors have paid a fee to allow immediate free access to this article.

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Journal of Virology, December 2009, p. 12151-12163, Vol. 83, No. 23
0022-538X/09/$08.00+0     doi:10.1128/JVI.01351-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.