REATMENT OF HUMAN IMMUNOdeficiency virus type 1 (HIV-1) infection with highly active antiretroviral therapy (HAART) can suppress viremia to below the limit of detection of available clinical assays. 1-3 The current goal of antiretroviral therapy is suppression of viremia to below 50 copies/mL of HIV-1 RNA, the limit of detection of the most sensitive available clinical assay. 4,5 Suppression to this level is necessary to prevent drug resistance, the major cause of treatment failure. 6,7 After achieving suppression, many patients experience intermittent episodes of detectable viremia ("blips"). 8-16 Blips may raise concern that resistance is developing and complicate management by increasing patient anxiety, triggering costly repeat measurements of viral load, and generating uncertainty re

Resting CD4؉ T-cell populations from human immunodeficiency virus type 1 (HIV- 1

The development of highly active antiretroviral therapy (HAART) to treat individuals infected with HIV-1 has dramatically improved patient outcomes, but HAART still fails to cure the infection. The latent viral reservoir in resting CD4 + T cells is a major barrier to virus eradication. Elimination of this reservoir requires reactivation of the latent virus. However, strategies for reactivating HIV-1 through nonspecific T cell activation have clinically unacceptable toxicities. We describe here the development of what we believe to be a novel in vitro model of HIV-1 latency that we used to search for compounds that can reverse latency. Human primary CD4 + T cells were transduced with the prosurvival molecule Bcl-2, and the resulting cells were shown to recapitulate the quiescent state of resting CD4 + T cells in vivo. Using this model system, we screened small-molecule libraries and identified a compound that reactivated latent HIV-1 without inducing global T cell activation, 5-hydroxynaphthalene-1,4-dione (5HN). Unlike previously described latency-reversing agents, 5HN activated latent HIV-1 through ROS and NF-κB without affecting nuclear factor of activated T cells (NFAT) and PKC, demonstrating that TCR pathways can be dissected and utilized to purge latent virus. Our study expands the number of classes of latency-reversing therapeutics and demonstrates the utility of this in vitro model for finding strategies to eradicate HIV-1 infection.

Summary Integrated HIV-1 genomes are found within actively transcribed host genes in latently infected CD4+ T cells. Readthrough transcription of the host gene might therefore suppress HIV-1 gene expression and promote the latent infection that allows viral persistence in patients on therapy. To address the effect of host gene readthrough, we used homologous recombination to insert HIV-1 genomes in either orientation into an identical position within an intron of an active host gene (HPRT). Constructs were engineered to permit or block readthrough transcription of HPRT. Readthrough transcription inhibited HIV-1 gene expression for convergently orientated provirus but enhanced HIV-1 gene expression when HIV-1 was in the same orientation as the host gene. Orientation had a >10 fold effect on HIV-1 gene expression. Due to the nature of HIV-1 integration sites in vivo, this orientation-dependent regulation can influence the vast majority of infected cells and adds another complexity to the maintenance of latency.