Chemokine receptor antagonists constitute a novel class of HIV-1 inhibitors that bind to cellular proteins on the surface of CD4+ T-cells and macrophages that serve as co-receptors for HIV-1. Escape of HIV-1 from inhibition by CCR5 antagonists occurs by two mechanisms?emergence of CXCR4-using viruses or emergence of viruses that remain R5 but have adapted to use CCR5 for entry despite the presence of inhibitory concentrations of CCR5 antagonists. Work completed during the current funding period has led to the characterization of vicriviroc (VCV)-resistant clinical isolates of HIV-1 subtype B and C. These viruses share a number of properties, including accumulation of mutations in the stems of the V3 loop, stimulation of replication by VCV (suggesting VCV dependence for engaging CCR5) and reduced entry kinetics compared to wild-type that are restored in the presence of VCV. Given the relatively small number of CCR5 antagonistresistant isolates studied to date, much remains to be learned about the mechanisms of escape from CCR5 antagonists. The shared features of viruses resistant to small-molecule CCR5 antagonists suggest that VCVresistant viruses can serve as an excellent model for CCR5 antagonist resistance.
Specific aims for the extension period of this project are as follows: 1) To complete a detailed assessment of entry kinetics of vicriviroc-resistant HIV-1. The entry kinetics of VCV-resistant HIV-1 will be explored over a range of CCR5 and CD4 levels using Affinofile cells in the presence of various concentrations of VCV or TAK-779. 2)To determine affinity of CCR5 antagonist-resistant HIV-1 envelopes for CD4 and CCR5. The ability of monomeric gp120 or trimeric HIV-1 envelope glycoproteins resistant to the CCR5 antagonists to bind CCR5- expressing cells will be examined in collaboration with Dr. Navid Madani using established protocols. 3)To explore associations between HIV-1 co-receptor usage and host genetic factors. We will make use of an existing genome-wide SNP database and high-resolution HLA haplotyping on a subcohort of 716 treatmentnaive patients to explore the hypothesis that host genetic factors are associated with emergence of CXCR4- usino virLis.

Public Health Relevance

Small-molecule CCR5 continue to offer promise, particularly as components of initial regimens in patients less likely to carry CXCR4-using variants and as agents to prevent HIV-1 transmission. Better understanding of resistance to this class of drugs is essential to their appropriate clinical use, and will shed important light on basic mechanisms of HIV-1 envelope/coreceptor interactions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI055357-12
Application #
8687576
Study Section
No Study Section (in-house review) (NSS)
Program Officer
Ussery, Michael A
Project Start
2003-04-01
Project End
2017-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
12
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02115
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Henrich, Timothy J; Hanhauser, Emily; Hu, Zixin et al. (2015) Viremic control and viral coreceptor usage in two HIV-1-infected persons homozygous for CCR5 Δ32. AIDS 29:867-76
Henrich, Timothy J; McLaren, Paul J; Rao, Suhas S P et al. (2014) Genome-Wide Association Study of Human Immunodeficiency Virus (HIV)-1 Coreceptor Usage in Treatment-Naive Patients from An AIDS Clinical Trials Group Study. Open Forum Infect Dis 1:ofu018
Lin, Nina H; Becerril, Carlos; Giguel, Francoise et al. (2012) Env sequence determinants in CXCR4-using human immunodeficiency virus type-1 subtype C. Virology 433:296-307
Putcharoen, Opass; Lee, Sun Hee; Henrich, Timothy J et al. (2012) HIV-1 clinical isolates resistant to CCR5 antagonists exhibit delayed entry kinetics that are corrected in the presence of drug. J Virol 86:1119-28
Tsibris, Athe M N; Hu, Zixin; Paredes, Roger et al. (2012) Vicriviroc resistance decay and relative replicative fitness in HIV-1 clinical isolates under sequential drug selection pressures. J Virol 86:6416-26
Henrich, Timothy J; Lewine, Nicolas R P; Lee, Sun-Hee et al. (2012) Differential use of CCR5 by HIV-1 clinical isolates resistant to small-molecule CCR5 antagonists. Antimicrob Agents Chemother 56:1931-5
Tsibris, Athe M N; Pal, Urboshi; Schure, Allison L et al. (2011) SHIV-162P3 infection of rhesus macaques given maraviroc gel vaginally does not involve resistant viruses. PLoS One 6:e28047
Kuritzkes, Daniel R (2011) Drug resistance in HIV-1. Curr Opin Virol 1:582-9

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