Caractérisation immunologique du réservoir cellulaire du VIH-1 en primo-infection et dans des modèles de contrôle spontané ou thérapeutique de l'infection

La persistance du réservoir VIH empêche l éradication du virus. L'atteinte d'un état stable de rémission fonctionnelle est une alternative à l absence d'éradication et suggère l intérêt de limiter l établissement des réservoirs latents qui peut être achevé lors d une prise en charge thérapeutique précoce. Nous avons étudié l'impact d'un traitement antirétroviral précoce sur la dynamique cellulaire et tissulaire du réservoir VIH-1 au moment de sa constitution en primo-infection, des années après un contrôle thérapeutique précoce et lors du contrôle spontané après interruption du traitement précoce des Post-Treatment Controllers (PTC). Nous avons montré que le réservoir est constitué dès le premier mois de l'infection dans les différentes sous-populations de lymphocytes T CD4 naïfs et mémoires quiescents. Sa dissémination résulte d'un cluster viral homogène dans les compartiments périphérique et rectal et perturbe l'homéostasie lymphocytaire T CD4, résultant en une contribution mineure au réservoir des lymphocytes quiescents naïfs (TN) et de type mémoire centrale (TCM) à longue durée de vie. La mise sous traitement précoce induit une réduction de la taille et une restriction de la diversité génétique du réservoir. Elle semble figer les anomalies homéostatiques du compartiment lymphocytaire T CD4 et confère des contributions différentes au réservoir à la périphérie et au rectum. Plus de deux ans de traitement précoce sont nécessaires pour atteindre les bas niveaux de réservoir observés chez les PTC, dont la faible contribution au réservoir des TCM et TN est associée au contrôle à long terme de l'infection. Ces travaux soulignent l'importance non seulement de limiter la taille du réservoir VIH-1, mais aussi de moduler sa composition, afin d atteindre une rémission fonctionnelle. Le traitement précoce et prolongé ouvre de nouvelles perspectives quant à l'obtention d'un équilibre entre le virus et son hôte permettant l'arrêt des traitements antirétroviraux et le contrôle à long terme de l infection à VIH-1.Eradication of HIV-1 is hindered by the latent reservoir persistence. Reaching a functional cure is an alternative to the lack of viral eradication, and underlines the benefit of limiting the reservoirs establishment by early antiretroviral therapy (ART). We studied the impact of early-ART on the cellular and tissular reservoir dynamics when it is constituted in acute infection, years after an early therapeutic control, and in the spontaneous control of infection after interruption of early-ART in Post-Treatment Controllers (PTC). We showed that the reservoir is established within the first month of infection in the various resting naive and memory CD4 T cell subsets. This dissemination resulted from one homogeneous viral cluster in both the peripheral and the rectal compartments, thus inducing a skewed CD4 T cell homeostasis resulting in a minor contribution to the HIV-1 reservoir of long-lived resting naive and central-memory CD4+ T cell subsets. Initiation of early-ART induced a decrease in the reservoir size and a restriction in its viral diversity. It also seemed to freeze the CD4 T cell compartment homeostatic abnormalities, imparting different contributions to the peripheral and the rectal compartments to the overall reservoir. More than 2 years of early-HAART are necessary to reach the low reservoirs found in PTC, whose poor TCM and TN cell contribution to the HIV reservoir is associated with their long-term control over infection. This work underlines the importance not only of limiting HIV-1 reservoirs size but also of impacting its composition, in order to reach a functional cure. Early-ART opens new perspectives as to reaching a stable equilibrium between the virus and its host, allowing interruption of antiretroviral therapy and long-term control over HIV-1 infection.PARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Estimating the contribution of CD4 T cell subset proliferation and differentiation to HIV persistence

Persistence of HIV in people living with HIV (PWH) on suppressive antiretroviral therapy (ART) has been linked to physiological mechanisms of CD4+ T cells. Here, in the same 37 male PWH on ART we measure longitudinal kinetics of HIV DNA and cell turnover rates in five CD4 cell subsets: naïve (TN), stem-cell- (TSCM), central- (TCM), transitional- (TTM), and effector-memory (TEM). HIV decreases in TTM and TEM but not in less-differentiated subsets. Cell turnover is ~10 times faster than HIV clearance in memory subsets, implying that cellular proliferation consistently creates HIV DNA. The optimal mathematical model for these integrated data sets posits HIV DNA also passages between CD4 cell subsets via cellular differentiation. Estimates are heterogeneous, but in an average participant's year ~10 (in TN and TSCM) and ~104 (in TCM, TTM, TEM) proviruses are generated by proliferation while ~103 proviruses passage via cell differentiation (per million CD4). In simulations, therapies blocking proliferation and/or enhancing differentiation could reduce HIV DNA by 1-2 logs over 3 years. In summary, HIV exploits cellular proliferation and differentiation to persist during ART but clears faster in more proliferative/differentiated CD4 cell subsets and the same physiological mechanisms sustaining HIV might be temporarily modified to reduce it

HIV-1 Genomes Are Enriched in Memory CD4+ T-Cells with Short Half-Lives.

Future HIV-1 curative therapies require a thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets during antiretroviral therapy (ART) and the cellular mechanisms that maintain this reservoir. Therefore, we sequenced near-full-length HIV-1 genomes and identified genetically-intact and genetically-defective genomes from resting naive, stem-cell memory, central memory, transitional memory, effector memory, and terminally-differentiated CD4+ T-cells with known cellular half-lives from 11 participants on ART. We find that a higher infection frequency with any HIV-1 genome was significantly associated with a shorter cellular half-life, such as transitional and effector memory cells. A similar enrichment of genetically-intact provirus was observed in these cells with relatively shorter half-lives. We found that effector memory and terminally-differentiated cells also had significantly higher levels of expansions of genetically-identical sequences, while only transitional and effector memory cells contained genetically-intact proviruses that were part of a cluster of identical sequences. Expansions of identical sequences were used to infer cellular proliferation from clonal expansion. Altogether, this indicates that specific cellular mechanisms such as short half-life and proliferative potential contribute to the persistence of genetically-intact HIV-1. IMPORTANCE The design of future HIV-1 curative therapies requires a more thorough understanding of the distribution of genetically-intact HIV-1 within T-cell subsets as well as the cellular mechanisms that maintain this reservoir. These genetically-intact and presumably replication-competent proviruses make up the latent HIV-1 reservoir. Our investigations into the possible cellular mechanisms maintaining the HIV-1 reservoir in different T-cell subsets have revealed a link between the half-lives of T-cells and the level of proviruses they contain. Taken together, we believe our study shows that more differentiated and proliferative cells, such as transitional and effector memory T-cells, contain the highest levels of genetically-intact proviruses, and the rapid turnover rate of these cells contributes to the expansion of genetically-intact proviruses within them. Therefore, our study delivers an in-depth assessment of the cellular mechanisms, such as cellular proliferation and half-life, that contribute to and maintain the latent HIV-1 reservoir

Combined ART started during acute HIV infection protects central memory CD4+ T cells and can induce remission

International audienceBACKGROUND: Therapeutic control of HIV replication reduces the size of the viral reservoir, particularly among central memory CD4+ T cells, and this effect might be accentuated by early treatment. METHODS: We examined the effect of ART initiated at the time of the primary HIV infection (early ART), lasting 2 and 6 years in 11 and 10 patients, respectively, on the HIV reservoir in peripheral resting CD4+ T cells, sorted into naive (TN), central memory (TCM), transitional memory (TTM) and effector memory (TEM) cells, by comparison with 11 post-treatment controllers (PTCs). RESULTS: Between baseline and 2 years, CD4+ T cell subset numbers increased markedly (P \textless 0.004) and HIV DNA levels decreased in all subsets (P \textless 0.009). TTM cells represented the majority of reservoir cells at both timepoints, T cell activation status normalized and viral diversity remained stable over time. The HIV reservoir was smaller after 6 years of early ART than after 2 years (P \textless 0.019), and did not differ between PTCs and patients treated for 6 years. One patient, who had low reservoir levels in all T cell subsets after 2 years of treatment similar to the levels in PTCs, spontaneously controlled viral replication during 18 months off treatment. CONCLUSIONS: Early prolonged ART thus limits the size of the HIV reservoir, protects long-lived cells from persistent infection and may enhance post-treatment control

A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI). We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM]) and short-lived (transitional-memory [TTM] and effector-memory cells [TEM]) resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells), although 10-fold less (p = 0.0005) than in equally infected TCM (4.5), TTM (4.7) and TEM (4.6) cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells), unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells). The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility, suggesting that subset activation and skewed immune homeostasis determine the conditions of viral dissemination and early establishment of the HIV reservoir

Post-treatment HIV-1 controllers with a long-term virological remission after the interruption of early initiated antiretroviral therapy ANRS VISCONTI Study

International audienceCombination antiretroviral therapy (cART) reduces HIV-associated morbidities and mortalities but cannot cure the infection. Given the difficulty of eradicating HIV-1, a functional cure for HIV-infected patients appears to be a more reachable short-term goal. We identified 14 HIV patients (post-treatment controllers [PTCs]) whose viremia remained controlled for several years after the interruption of prolonged cART initiated during the primary infection. Most PTCs lacked the protective HLA B alleles that are overrepresented in spontaneous HIV controllers (HICs); instead, they carried risk-associated HLA alleles that were largely absent among the HICs. Accordingly, the PTCs had poorer CD8+ T cell responses and more severe primary infections than the HICs did. Moreover, the incidence of viral control after the interruption of early antiretroviral therapy was higher among the PTCs than has been reported for spontaneous control. Off therapy, the PTCs were able to maintain and, in some cases, further reduce an extremely low viral reservoir. We found that long-lived HIV-infected CD4+ T cells contributed poorly to the total resting HIV reservoir in the PTCs because of a low rate of infection of naïve T cells and a skewed distribution of resting memory CD4+ T cell subsets. Our results show that early and prolonged cART may allow some individuals with a rather unfavorable background to achieve long-term infection control and may have important implications in the search for a functional HIV cure

The HIV-1 proviral landscape reveals that Nef contributes to HIV-1 persistence in effector memory CD4+ T cells.

Despite long-term antiretroviral therapy (ART), HIV-1 persists within a reservoir of CD4+ T cells that contribute to viral rebound if treatment is interrupted. Identifying the cellular populations that contribute to the HIV-1 reservoir and understanding the mechanisms of viral persistence are necessary to achieve an effective cure. In this regard, through Full-Length Individual Proviral Sequencing, we observed that the HIV-1 proviral landscape was different and changed with time on ART across naive and memory CD4+ T cell subsets isolated from 24 participants. We found that the proportion of genetically intact HIV-1 proviruses was higher and persisted over time in effector memory CD4+ T cells when compared with naive, central, and transitional memory CD4+ T cells. Interestingly, we found that escape mutations remained stable over time within effector memory T cells during therapy. Finally, we provided evidence that Nef plays a role in the persistence of genetically intact HIV-1. These findings posit effector memory T cells as a key component of the HIV-1 reservoir and suggest Nef as an attractive therapeutic target

Relationship between CD4 T cell turnover, cellular differentiation and HIV persistence during ART.

The precise role of CD4 T cell turnover in maintaining HIV persistence during antiretroviral therapy (ART) has not yet been well characterized. In resting CD4 T cell subpopulations from 24 HIV-infected ART-suppressed and 6 HIV-uninfected individuals, we directly measured cellular turnover by heavy water labeling, HIV reservoir size by integrated HIV-DNA (intDNA) and cell-associated HIV-RNA (caRNA), and HIV reservoir clonality by proviral integration site sequencing. Compared to HIV-negatives, ART-suppressed individuals had similar fractional replacement rates in all subpopulations, but lower absolute proliferation rates of all subpopulations other than effector memory (TEM) cells, and lower plasma IL-7 levels (p = 0.0004). Median CD4 T cell half-lives decreased with cell differentiation from naïve to TEM cells (3 years to 3 months, p<0.001). TEM had the fastest replacement rates, were most highly enriched for intDNA and caRNA, and contained the most clonal proviral expansion. Clonal proviruses detected in less mature subpopulations were more expanded in TEM, suggesting that they were maintained through cell differentiation. Earlier ART initiation was associated with lower levels of intDNA, caRNA and fractional replacement rates. In conclusion, circulating integrated HIV proviruses appear to be maintained both by slow turnover of immature CD4 subpopulations, and by clonal expansion as well as cell differentiation into effector cells with faster replacement rates

Relationship between CD4 T cell turnover, cellular differentiation and HIV persistence during ART.

The precise role of CD4 T cell turnover in maintaining HIV persistence during antiretroviral therapy (ART) has not yet been well characterized. In resting CD4 T cell subpopulations from 24 HIV-infected ART-suppressed and 6 HIV-uninfected individuals, we directly measured cellular turnover by heavy water labeling, HIV reservoir size by integrated HIV-DNA (intDNA) and cell-associated HIV-RNA (caRNA), and HIV reservoir clonality by proviral integration site sequencing. Compared to HIV-negatives, ART-suppressed individuals had similar fractional replacement rates in all subpopulations, but lower absolute proliferation rates of all subpopulations other than effector memory (TEM) cells, and lower plasma IL-7 levels (p = 0.0004). Median CD4 T cell half-lives decreased with cell differentiation from naïve to TEM cells (3 years to 3 months, p<0.001). TEM had the fastest replacement rates, were most highly enriched for intDNA and caRNA, and contained the most clonal proviral expansion. Clonal proviruses detected in less mature subpopulations were more expanded in TEM, suggesting that they were maintained through cell differentiation. Earlier ART initiation was associated with lower levels of intDNA, caRNA and fractional replacement rates. In conclusion, circulating integrated HIV proviruses appear to be maintained both by slow turnover of immature CD4 subpopulations, and by clonal expansion as well as cell differentiation into effector cells with faster replacement rates