Open AccessGenetic Diversity of Simian Immunodeficiency Virus Encoding HIV-1 Reverse Transcriptase Persists in Macaques despite Antiretroviral Therapy
Author(s) -
Mary F. Kearney,
Jonathan Spindler,
Wei Shao,
Frank Maldarelli,
Sarah Palmer,
Shiu Lok Hu,
Jeffrey D. Lifson,
Vineet N. KewalRamani,
John W. Mellors,
John M. Coffin,
Zandrea Ambrose
Publication year - 2011
Publication title -
journal of virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.617
H-Index - 292
eISSN - 1070-6321
pISSN - 0022-538X
DOI - 10.1128/jvi.01701-10
Subject(s) - biology , viremia , virology , simian immunodeficiency virus , macaque , efavirenz , viral load , virus , reverse transcriptase , population , lentivirus , genetics , viral disease , antiretroviral therapy , polymerase chain reaction , gene , medicine , paleontology , environmental health
The impact of antiretroviral therapy (ART) on the genetics of simian immunodeficiency virus (SIV) or human immunodeficiency virus (HIV) populations has been incompletely characterized. We analyzed SIV genetic variation before, during, and after ART in a macaque model. Six pigtail macaques were infected with an SIV/HIV chimeric virus, RT-SHIVmne , in which SIV reverse transcriptase (RT) was replaced by HIV-1 RT. Three animals received a short course of efavirenz (EFV) monotherapy before combination ART was started. All macaques received 20 weeks of tenofovir, emtricitabine, and EFV. Plasma virus populations were analyzed by single-genome sequencing. Population diversity was measured by average pairwise difference, and changes in viral genetics were assessed by phylogenetic and panmixia analyses. After 20 weeks of ART, viral diversity was not different from pretherapy viral diversity despite more than 10,000-fold declines in viremia, indicating that, within this range, there is no relationship between diversity and plasma viremia. In two animals with consistent SIV RNA suppression to 15 copies/ml during therapy, there was divergence between pre- and during-ART virus populations. Drug resistance mutations emerged in two of these four animals, resulting in virologic failure in the animal with the highest level of pretherapy viremia. Taken together, these findings indicate that viral diversity does not decrease with suppressive ART, that ongoing replication occurs with viremias >15 copies/ml, and that in this macaque model of ART drug resistance likely emerges as a result of incomplete suppression and preexisting drug resistance mutations.