Choice of antiretroviral therapy differentially impacts survival of HIV-infected CD4 T cells.

Nathan W Cummins,Andrew D Badley,Amy M Sainski,Sekar Natesampillai,Gary D Bren

doi:10.1186/2052-8426-2-1

Abstract

BackgroundHIV eradication strategies are now being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). Since many antiretroviral agents have off target effects, and different classes target different components of the viral life cycle, we questioned whether different classes of ART might differentially affect the survival and persistence of productively HIV-infected CD4 T cells.MethodsIn vitro infections of primary CD4 T cells using clinical isolates of HIV-1 that were either protease inhibitor susceptible (HIV PI-S), or resistant (HIV PI-R) were treated with nothing, lopinavir, efavirenz or raltegravir. Cell viability, apoptosis, and the proportion of surviving cells that were P24 positive was assessed by flow cytometry.ResultsIn HIV PI-S infected primary cultures, all three antiretroviral agents decreased viral replication, and reduced the total number of cells that were undergoing apoptosis (P < 0.01) similarly. Similarly, in the HIV PI-R infected cultures, both efavirenz and raltegravir reduced viral replication and reduced apoptosis compared to untreated control (P < 0.01), while lopinavir did not, suggesting that HIV replication drives T cell apoptosis, which was confirmed by association by linear regression (P < 0.0001) . However since HIV protease has been suggested to directly induce apoptosis of infected CD4 T cells, and HIV PI are intrinsically antiapoptotic, we evaluated apoptosis in productively infected (HIV P24+) cells. More HIV p24 positive cells were apoptotic in the Efavirenz or raltegravir treated cultures than the lopinavir treated cultures (P = 0.0008 for HIV PI-R and P = 0.06 for the HIV PI-S), indicating that drug class impacts survival of productively infected CD4 T cells.ConclusionsInhibiting HIV replication with a PI, NNRTI or INSTI reduces total HIV-induced T cell apoptosis. However, blocking HIV replication with PI but not with NNRTI or INSTI promotes survival of productively HIV-infected cells. Thus, selection of antiretroviral agents may impact the success of HIV eradication strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/2052-8426-2-1) contains supplementary material, which is available to authorized users.

Highlights

Human immunodeficiency virus (HIV) eradication strategies are being evaluated in vitro and in vivo
Lopinavir (100 nM) decreased HIV protease cleavage of procaspase 8 by >90% compared to untreated control, whereas a lower dose (10 nM) of lopinavir, raltegravir (10 and 100 nM), and efavirenz (1 and 10 nM) did not (Additional file 1: Figure S1)
Since Casp8p41 is only present in productively-infected cells [17], these data suggest that lopinavir may inhibit apoptosis of productively-infected cells through this unique mechanism

Summary

Introduction

HIV eradication strategies are being evaluated in vitro and in vivo. A cornerstone of such approaches is maximal suppression of viral replication with combination antiretroviral therapy (ART). The latent reservoir consists principally of integrated provirus within central memory CD4 T cells These are thought to arise in one of two non-mutually exclusive ways: direct infection of central memory cells, or infection of activated cells which revert to a memory phenotype. These models predict that the size of the latent reservoir is proportional to the cumulative number of productively infected cells. This prediction has been tested and verified in vivo [6,7,8]. It is of interest to understand factors which influence the size of this ‘active reservoir’ of HIV

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Conclusion