CROI 2018 Abstract eBook

Abstract eBook

Oral Abstracts

competent proviruses in individuals on suppressive antiretroviral therapy. However, a recent study revealed a clonal population of infected CD4+ T cells carrying replication-competent HIV-1 that led to persistent plasma viremia in a patient with squamous cell carcinoma. We hypothesize that clones harboring replication-competent provirus expand and contract overtime. Methods: To determine whether expanded clones harboring replication- competent virus persist, we recovered the infectious virus from 8 infected individuals at 2 or 3 time points spanning 2 to 3 years apart. We amplified the highly variable V3-V4 region of the env gene by RT-PCR from viral RNA in the supernatants of all p24+ wells from the QVOA. Sequences from each individual were clustered for phylogenetic analysis. Results: Longitudinal sampling of replication-competent virus from all 8 participants revealed that they all have one or more sets of independent isolates with identical env sequences at all time points. In 7 out of 8 individuals, we found sequences that were present and prevalent at time point 1, at time point 2 or time point 3, suggesting some clones persisted overtime. In 7 out of 8 individuals, we observed clonal populations carrying different replication- competent viruses at time point 2 and time point 3. Conclusion: We showed that the clonal populations harboring replication- competent HIV-1 change overtime. The result revealed that expanded clones carrying infectious HIV-1 in the latent reservoir wax and wane. The finding will help us to model what mechanism contributes to persistence of the latent reservoir. 69LB DETERMINANTS OF HIV-1 RESERVOIR SIZE AND LONG-TERM DYNAMICS UNDER SUPPRESSIVE ART Nadine Bachmann 1 , Chantal von Siebenthal 1 , Valentina Vongrad 1 , Kathrin Neumann 1 , Teja Turk 1 , Niko Beerenwinkel 2 , Jasmina Bogojeska 3 , Jacques Fellay 4 , Volker Roth 5 , Roger Kouyos 1 , Karin Metzner 1 , Huldrych F. Günthard 1 1 University Hospital Zurich, Zurich, Switzerland, 2 ETH Zurich, Zurich, Switzerland, 3 IBM Research–Zurich, Zurich, Switzerland, 4 École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 5 University of Basel, Basel, Switzerland Background: The HIV-1 reservoir is the major hurdle to cure. Thus, understanding factors affecting size and decay of this reservoir is crucial for development of cure strategies. Methods: In 1,078 patients (pt) enrolled in the Swiss HIV Cohort Study, who after initiating their 1st triple combination antiretroviral therapy (cART) were fully suppressed for >5 yr (< 50 HIV RNA cp/ml of plasma), we measured total HIV-1 DNA levels at 3-4 time points using droplet digital PCR (in total 3,546 samples). Focusing on the time after the 1st rapid decay of HIV-1 DNA we chose the 1. time point 1.49 yr (IQR=[1.27,1.7], N=1,078) after ART initiation, the 2. time point 2 yr later (IQR=[1.87,2.16], N=1,068) and the 3. time point on average 1.93 yr (IQR=[1.77,2.15], N=1,071) thereafter. Total HIV-1 DNA in a 4th sample was quantified for a subset of pt 4.92 yr (IQR=[3.28,6.02], N=429) later. This extensive data set enabled a systematic investigation of parameters that potentially steer decay dynamics of the HIV-1 reservoir in infected individuals on long-term successful ART. Results: Total HIV-1 DNA levels significantly decreased between our sampling times with diminishing differences over time (Fig 1). Further, our data identified pre-cART RNA levels, viral subtype, risk group injecting drug user, time to suppression, blips before 1st sample and infection stage at cART start to be independent drivers of the initial total HIV-1 DNA level. Studying decay slopes for each pt, pre-cART CD4 cell count, pre-cART CD4/CD8 ratio, pre-cART viral load and viral blips were significant drivers in the univariate model. The type of treatment (NNRTI vs boosted PI based cART) showed no differential effect on the decay. However, in multivariable analysis a very strong and independent inhibitory effect on total HIV-1 DNA decay was governed by viral blips. To conclude, our data confirm relevant drivers of the establishment and the depletion of the viral reservoir and reflect a highly interesting causal interplay between intermittent replication and dynamics of total HIV-1 DNA of patients on successful therapy. Conclusion: The size of the viral reservoir as measured by total HIV-1 DNA in this large study is strongly governed by time of cART initiation. Strikingly, the main independent predictor of total HIV-1 DNA decay were viral blips, which had a strong inhibiting effect. Thus, viral blips are of biological relevance for the latent reservoir and this may have implications for cure research.

Oral Abstracts

67 CD8+ T CELL RESPONSES IN TREATED HYPERACUTE HIV INFECTION LIMIT HIV RESERVOIR SIZE Zaza Ndhlovu 1 , Samuel W. Kazer 2 , Thandeka Nkosi 3 , Funsho Ogunshola 3 , Amber D. Moodley 3 , Krista Dong 1 , Alex K. Shalek 2 , Thumbi Ndungú 3 , Bruce D. Walker 1 1 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA, 2 MIT Institute for Medical Engineering & Science, Cambridge, MA, USA, 3 University of KwaZulu-Natal, Durban, South Africa Background: Early initiation of cART has the potential to enhance protective immunity by preserving CD4+ T cells and limiting T cell exhaustion. However, the quality of HIV-specific CD8+ T responses induced in the context of limited HIV antigen exposure and the impact on the dynamics of HIV reservoir accumulation are underexplored. Methods: Studies were performed in persons identified and treated at the onset of HIV plasma viremia (n=34, 27 Fiebig Stage I, 7 Fiebig stage III/V), and compared to chronic treated persons (n=10). Flow cytometry and transcriptional analyses coupled with HIV DNA measurements were used to longitudinally define the relationships between HIV-specific CD8+ T cells responses, viral persistence and reservoir decay. Results: More than 90% of individuals initiating treatment in Fiebig I mounted detectable HIV-specific CD8+ T cell responses. The breadth of the initial responses was driven by cumulative HIV plasma viral burden (viremia copy days, VCD), defined as the area under plasma viral load curve. There was a strong positive correlation between VCD and immune responses measured by three different assays namely, activation (CD8+CD38+HLA-DR+) (r=0.08, p=0.0001), frequency of tetramer+ CD8+ T cells (r=0.8, p=0.006) and breadth of HIV- specific CD8+ T cell responses measured by IFN-γ ELISPOT (r=0.5, p=0.02). Tetramer-stained HIV-specific CD8+ T responses of early treated subjects had significantly higher expression of CD127 (p=0.0009) and had a pro-survival transcriptional profile compared to responses from untreated hyperacute HIV infection. The breadth of HIV-specific CD8+ T cells measured by IFN-γ ELISPOT positively correlated with HIV DNA reservoir decay over a one-year period (r=0.8, p=0.04). Conclusion: These results demonstrate that HIV-specific CD8+ T cell responses generated in early treated persons exhibit enhanced CD127 expression, and the breadth of early responses is associated with reservoir decay. Together these data suggest that early therapy enhances HIV-specific CD8+ T cell function, and provide important parameters by which to evaluate antiviral function induced by prophylactic and therapeutic vaccines. 68 EXPANDED CLONES HARBORING REPLICATION-COMPETENT VIRUS WAX AND WANE OVERTIME Zheng Wang 1 , Mithra R. Kumar 1 , Janet Siliciano 1 , Robert Siliciano 1 1 The Johns Hopkins University, Baltimore, MD, USA Background: The latent reservoir for HIV-1 in resting CD4+ T cells is a major barrier to cure. Recent studies suggest that the latent reservoir could be maintained through cellular proliferation. Several mechanisms potentially contribute to persistence of latently infected cells, including antigen-driven cell expansion, homeostatic proliferation and proliferation driven by effects related to the site of HIV-1 integration. Most infected cells carry defective proviruses, and only ~1/10-6 resting CD4+ T cells carry inducible replication-

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CROI 2018