Protein expression from unintegrated HIV-1 DNA introduces bias in primary in vitro post-integration latency models

Sci Rep. 2016 Dec 2:6:38329. doi: 10.1038/srep38329.

Abstract

To understand the persistence of latently HIV-1 infected cells in virally suppressed infected patients, a number of in vitro models of HIV latency have been developed. In an attempt to mimic the in vivo situation as closely as possible, several models use primary cells and replication-competent viruses in combination with antiretroviral compounds to prevent ongoing replication. Latency is subsequently measured by HIV RNA and/or protein production after cellular activation. To discriminate between pre- and post-integration latency, integrase inhibitors are routinely used, preventing novel integrations upon cellular activation. Here, we show that this choice of antiretrovirals may still cause a bias of pre-integration latency in these models, as unintegrated HIV DNA can form and directly contribute to the levels of HIV RNA and protein production. We further show that the addition of reverse transcriptase inhibitors effectively suppresses the levels of episomal HIV DNA (as measured by 2-LTR circles) and decreases the levels of HIV transcription. Consequently, we show that latency levels described in models that only use integrase inhibitors may be overestimated. The inclusion of additional control conditions, such as 2-LTR quantification and the addition of reverse transcriptase inhibitors, is crucial to fully elucidate the actual levels of post-integration latency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes
  • Benzoxazines / pharmacology
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / virology
  • Cyclopropanes
  • DNA, Viral / antagonists & inhibitors
  • DNA, Viral / biosynthesis
  • DNA, Viral / genetics
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HIV Infections / drug therapy
  • HIV Infections / immunology
  • HIV Infections / virology
  • HIV Integrase Inhibitors / pharmacology*
  • HIV Protease Inhibitors / pharmacology*
  • HIV-1 / drug effects*
  • HIV-1 / physiology
  • Humans
  • Lymphocyte Activation
  • Models, Biological
  • Nevirapine / pharmacology
  • Primary Cell Culture
  • Raltegravir Potassium / pharmacology
  • Reverse Transcriptase Inhibitors / pharmacology*
  • Ritonavir / pharmacology
  • Viral Proteins / antagonists & inhibitors
  • Viral Proteins / biosynthesis
  • Viral Proteins / genetics*
  • Virus Integration / drug effects
  • Virus Latency / drug effects*
  • Virus Replication / drug effects

Substances

  • Alkynes
  • Benzoxazines
  • Cyclopropanes
  • DNA, Viral
  • HIV Integrase Inhibitors
  • HIV Protease Inhibitors
  • Reverse Transcriptase Inhibitors
  • Viral Proteins
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Raltegravir Potassium
  • Nevirapine
  • efavirenz
  • Ritonavir