The lymphocyte HIV reservoir in patients on long-term HAART is a memory of virus evolution

Generalized immune activation during HIV infection is associated with an increased risk of cardiovascular disease, neurocognitive disease, osteoporosis, metabolic disorders, and physical frailty. The mechanisms driving this immune activation are poorly understood, particularly for individuals effectively treated with antiretroviral medications. We hypothesized that viral characteristics such as sequence diversity may play a role in driving HIV-associated immune activation. We therefore sequenced proviral DNA isolated from peripheral blood mononuclear cells from HIV-infected individuals on fully suppressive antiretroviral therapy. We performed phylogenetic analyses, calculated viral diversity and divergence in the env and pol genes, and determined coreceptor tropism and the frequency of drug resistance mutations. Comprehensive immune profiling included quantification of immune cell subsets, plasma cytokine levels, and intracellular signaling responses in T cells, B cells, and monocytes. These antiretroviral therapy-treated HIV-infected individuals exhibited a wide range of diversity and divergence in both env and pol genes. However, proviral diversity and divergence in env and pol, coreceptor tropism, and the level of drug resistance did not significantly correlate with markers of immune activation. A clinical history of virologic failure was also not significantly associated with levels of immune activation, indicating that a history of virologic failure does not inexorably lead to increased immune activation as long as suppressive antiretroviral medications are provided. Overall, this study demonstrates that latent viral diversity is unlikely to be a major driver of persistent HIV-associated immune activation. IMPORTANCEChronic immune activation, which is associated with cardiovascular disease, neurologic disease, and early aging, is likely to be a major driver of morbidity and mortality in HIV-infected individuals. Although treatment of HIV with antiretroviral medications decreases the level of immune activation, levels do not return to normal. The factors driving this persistent immune activation, particularly during effective treatment, are poorly understood. In this study, we investigated whether characteristics of the latent, integrated HIV provirus that persists during treatment are associated with immune activation. We found no relationship between latent viral characteristics and immune activation in treated individuals, indicating that qualities of the provirus are unlikely to be a major driver of persistent inflammation. We also found that individuals who had previously failed treatment but were currently effectively treated did not have significantly increased levels of immune activation, providing hope that past treatment failures do not have a lifelong "legacy" impact.

Section: Discussionmentioning

confidence: 99%

Association between Latent Proviral Characteristics and Immune Activation in Antiretrovirus-Treated Human Immunodeficiency Virus Type 1-Infected Adults

Liang

Sceats

Bayless

et al. 2014

“…However, the HIV DNA reservoir is highly diverse, as it is derived from the successive archiving of circulating plasma viruses (30). In order to address the amount of viral diversity within the proviral reservoir, we have designed a novel targeted sequence capturebased method for HIV integration site sequencing that uses a pool of capture probes to account for HIV diversity (Fig.…”

Section: Importancementioning

confidence: 99%

HIV Integration Site Analysis of Cellular Models of HIV Latency with a Probe-Enriched Next-Generation Sequencing Assay

Sunshine

Kirchner

Amr

et al. 2016

Antiretroviral therapy (ART) is successful in the suppression of HIV but cannot target and eradicate the latent proviral reservoir. The location of retroviral integration into the human genome is thought to play a role in the clonal expansion of infected cells and HIV persistence. We developed a high-throughput targeted sequence capture assay that uses a pool of HIV-specific probes to enrich Illumina libraries prior to deep sequencing. Using an expanded clonal population of ACH-2 cells, we demonstrate that this sequence capture assay has an extremely low false-positive rate. This assay assessed four cellular models commonly used to study HIV latency and latency-reversing agents: ACH-2 cells, J-Lat cells, the Bcl-2-transduced primary CD4؉ model, and the cultured T CM (central memory) CD4؉ model. HIV integration site characteristics and genes were compared between these cellular models and to previously reported patient data sets. Across these cellular models, there were significant differences in integration site characteristics, including orientation relative to that of the host gene, the proportion of clonally expanded sites, and the proportion located within genic regions and exons. Despite a greater diversity of minority integration sites than expected in ACH-2 cells, their integration site characteristics consistently differed from those of the other models and from the patient samples. Gene ontology analysis of highly represented genes from the patient samples found little overlap with HIV-containing genes from the cell lines. These findings show that integration site differences exist among the commonly used cellular models of HIV latency and in comparison to integration sites found in patient samples. IMPORTANCEDespite the success of ART, currently there is no successful therapy to eradicate integrated proviruses. Cellular models of HIV latency are used to test the efficacy of latency-reversing agents, but it is unclear how well these models reflect HIV integration into the human genome in vivo. We have developed a novel probe-based sequence enrichment assay to sequence and analyze integrated HIV. We compared HIV integration site characteristics between four cellular models and to previously described patient data sets. Significant differences were detected in the distribution of HIV integration sites between cellular models of HIV latency and compared to data sets from patient samples. The results from this study have implications for how well these cellular models of HIV infection truly reflect HIV integration in vivo and their applicability in drug discovery for novel latency-reversing agents.

“…Since viruses can be continually deposited into the latent reservoir during periods of low-level viremia or during treatment failure and can exit the latent reservoir when their host cell is activated (10), latency provides a means for the archiving and reemergence of sequences representing the history of a patient's quasispecies. When drugresistant viruses are present, they are also archived in the latent reservoir (11)(12)(13)(14)(15). Since viral rebound from latently infected cells occurs upon treatment interruption or treatment failure (16), previously existing drug-resistant viruses that are present in the latent reservoir preclude patients from being treated with that drug or drug combination in the future.…”

mentioning

confidence: 99%

“…Recombination within individual patients has been documented in numerous studies (reviewed in reference 25), and recombination involving drug-resistant viruses provides a mechanism for the spread of drug resistance throughout a patient's quasispecies (28)(29)(30). Since the latent reservoir represents an archive of the history of a patient's quasispecies, including viruses with any previously existing drug resistance mutations (11)(12)(13)(14)(15), latent viruses represent an important source for the further generation of genetic diversity under selective pressure. This could occur following superinfection of a latently infected cell.…”

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confidence: 99%

Latent HIV-1 Can Be Reactivated by Cellular Superinfection in a Tat-Dependent Manner, Which Can Lead to the Emergence of Multidrug-Resistant Recombinant Viruses

Donahue

Bastarache

Sloan

et al. 2013

bThe HIV-1 latent reservoir represents an important source of genetic diversity that could contribute to viral evolution and multidrug resistance following latent virus reactivation. This could occur by superinfection of a latently infected cell. We asked whether latent viruses might be reactivated when their host cells are superinfected, and if so, whether they could contribute to the generation of recombinant viruses. Using populations of latently infected Jurkat cells, we found that latent viruses were efficiently reactivated upon superinfection. Pathways leading to latent virus reactivation via superinfection might include gp120-CD4/CXCR4-induced signaling, modulation of the cellular environment by Nef, and/or the activity of Tat produced upon superinfection. Using a range of antiviral compounds and genetic approaches, we show that gp120 and Nef are not required for latent virus reactivation by superinfection, but this process depends on production of functional Tat by the superinfecting virus. In a primary cell model of latency in unstimulated CD4 T cells, superinfection also led to latent virus reactivation. Drug-resistant latent viruses were also reactivated following superinfection in Jurkat cells and were able to undergo recombination with the superinfecting virus. Under drug-selective pressure, this generated multidrug-resistant recombinants that were identified by unique restriction digestion band patterns and by population-level sequencing. During conditions of poor drug adherence, treatment interruption or treatment failure, or in drug-impermeable sanctuary sites, reactivation of latent viruses by superinfection or other means could provide for the emergence or spread of replicatively fit viruses in the face of strong selective pressures.