Understanding HIV-1 persistence despite antiretroviral therapy (ART) is of paramount importance. Both single-genome sequencing (SGS) and integration site analysis (ISA) provide useful information regarding the structure of persistent HIV DNA populations; however, until recently, there was no way to link integration sites to their cognate proviral sequences. Here, we used multiple-displacement amplification (MDA) of cellular DNA diluted to a proviral endpoint to obtain full-length proviral sequences and their corresponding sites of integration. We applied this method to lymph node and peripheral blood mononuclear cells from 5 ART-treated donors to determine whether groups of identical subgenomic sequences in the 2 compartments are the result of clonal expansion of infected cells or a viral genetic bottleneck. We found that identical proviral sequences can result from both cellular expansion and viral genetic bottlenecks occurring prior to ART initiation and following ART failure. We identified an expanded T cell clone carrying an intact provirus that matched a variant previously detected by viral outgrowth assays and expanded clones with wild-type and drug-resistant defective proviruses. We also found 2 clones from 1 donor that carried identical proviruses except for nonoverlapping deletions, from which we could infer the sequence of the intact parental virus. Thus, MDA-SGS can be used for “viral reconstruction” to better understand intrapatient HIV-1 evolution and to determine the clonality and structure of proviruses within expanded clones, including those with drug-resistant mutations. Importantly, we demonstrate that identical sequences observed by standard SGS are not always sufficient to establish proviral clonality.

BACKGROUND: Naive cells comprise 90% of the CD4 ⁺ T cell population in neonates and exhibit distinct age-specific capacities for proliferation and activation. We hypothesized that HIV-infected naive CD4 ⁺ T cell populations in children on long-term antiretroviral therapy (ART) would thus be distinct from infected memory cells. METHODS: Peripheral blood naive and memory CD4 ⁺ T cells from 8 children with perinatal HIV on ART initiated at age 1.7–17 months were isolated by FACS. DNA was extracted from sorted cells, and HIV proviruses were counted, evaluated for intactness, and subjected to integration site analysis (ISA). RESULTS: Naive CD4 ⁺ T cells containing HIV proviruses were detected in children with 95% statistical confidence. A median 4.7% of long terminal repeat–containing naive CD4 ⁺ T cells also contained HIV genetic elements consistent with intactness. Full-length proviral sequencing confirmed intactness of 1 provirus. In the participant with the greatest degree of naive cell infection, ISA revealed infected expanded cell clones in both naive and memory T cells, with no common HIV integration sites detected between subsets. Divergent integration site profiles reflected differential gene expression patterns of naive and memory T cells. CONCLUSION: These results demonstrate that HIV persisted in both naive and memory CD4 ⁺ T cells that underwent clonal expansion and harbored intact proviruses, and suggest that infected memory T cell clones do not frequently arise from naive cell differentiation in children with perinatal HIV on long-term ART. FUNDING: Center for Cancer Research, NCI; Office of AIDS Research; NCI FLEX; Children’s and Emory Junior Faculty Focused Award.

Persons with HIV (PWH) receiving integrase (IN) strand transfer inhibitors (INSTIs) have been reported to experience virologic failure (VF) in the absence of resistance mutations in IN. We previously reported that mutations in the viral nucleocapsid (NC) are selected in the presence of the INSTI dolutegravir (DTG). Here, we show that these NC mutations accelerate the kinetics of viral DNA integration, suggesting that they limit the window of time available for INSTIs to block viral DNA integration. We find that in primary peripheral blood mononuclear cells, HIV-1 acquires mutations in the viral envelope glycoprotein, NC, and occasionally IN during selection for INSTI resistance. Notably, the selected NC and IN mutations act in concert to reduce the susceptibility of the virus to INSTIs. These results provide insights into the mechanism by which HIV-1 escapes the inhibitory activity of INSTIs and underscore the importance of genotypic analysis outside IN in PWH experiencing VF on INSTI-containing drug regimens.

Development of potential HIV-1 curative interventions requires accurate characterization of the proviral reservoir, defined as host-integrated viral DNA genomes that drive rebound of viremia upon halting ART (antiretroviral therapy). Evaluation of such interventions necessitates methods capable of pinpointing the rare, genetically intact, replication-competent proviruses within a background of defective proviruses. This evaluation can be achieved by identifying the distinct integration sites of intact proviruses within host genomes and monitoring the dynamics of these proviruses and host cell lineages over longitudinal sampling. Until recently, molecular genetic approaches at the single proviral level have been generally limited to one of a few metrics, such as proviral genome sequence/intactness, host-proviral integration site, or replication competency. New approaches, taking advantage of MDA (multiple displacement amplification) for WGA (whole genome amplification), have enabled multiparametric proviral characterization at the single-genome level, including proviral genome sequence, host-proviral integration site, and phenotypic characterization of the host cell lineage, such as CD4 memory subset and antigen specificity. In this review, we will examine the workflow of MDA-augmented molecular genetic approaches to study the HIV-1 reservoir, highlighting technical advantages and flexibility. We focus on a collection of recent studies in which investigators have used these approaches to comprehensively characterize intact and defective proviruses from donors on ART, investigate mechanisms of elite control, and define cell lineage identity and antigen specificity of infected CD4+ T cell clones. The highlighted studies exemplify how these approaches and their future iterations will be key in defining the targets and evaluating the impacts of HIV curative interventions.

HIV-1 proviral landscapes were investigated using near-full-length HIV single-genome sequencing on blood samples from five children with vertically acquired infection and on ART for ~7–9 years. Proviral structures were compared to published datasets in children prior to ART, children on short-term ART, and adults on ART. We found a strong selection for large internal proviral deletions in children, especially deletions of the env gene. Only 2.5% of the proviruses were sequence-intact, lower than in the comparative datasets from adults. Of the proviruses that retained the env gene, >80% contained two or more defects, most commonly stop codons and/or gag start mutations. Significantly fewer defects in the major splice donor site (MSD) and packaging signal were found in the children on short or long-term ART compared to the adults, and tat was more frequently defective in children. These results suggest that different selection pressures may shape the proviral landscape in children compared to adults and reveal potentially different genetic regions to target for measuring the intact HIV reservoir and for achieving HIV remission in children.