CROI 2015 Program and Abstracts

Abstract Listing

Oral Abstracts

Conclusions: This study highlights the rapidity and breadth of viral infiltration during AHI. Detectable colonic HIV RNA is common and correlates with increase HIV burden in the peripheral blood, colon, and CSF. Subjects with detectable colonic HIV RNA during AHI demonstrate colonic CD4 depletion, peripheral inflammation, and CD8+ T-cell activation in both colon and periphery. Subjects with undetectable colonic HIV RNA tended to be at earlier stages of AHI. 49 Identification and Characterization of Individual HIV-Infected CD4 T Cells Ex Vivo Joseph Casazza 1 ; Irene Primmer 1 ; David Ambrozak 1 ; Constantinos Petrovas 1 ; Sara Ferrando-Martinez 1 ; Perla Del Río-Estrada 2 ; Gustavo Reyes-Terán 2 ; Ezequiel Ruiz-Mateos 3 ; John Mascola 1 ; Richard A. Koup 1 1 Vaccine Research Center, NIAID, NIH, Bethesda, MD, US; 2 Instituto Nacional de Enfermedades Respiratorias, Mexico City, Mexico; 3 HU Virgen del Rocio/IBIS, Sevilla, Spain Background: Identification of live HIV-infected CD4 cells would allow the characterization of these cells by flow cytometry and single cell transcriptomic analysis. Methods: bnAbs were screened for their ability to identify individual BaL-infected primary CD4 T cells as identified by P24 intracellular staining and transcription of Gag, and D1A3 (Tat-associated) and D1A4b (Rev-associated) spliced HIV RNA. CD4 mimic, V1V2 and the V3 glycan bnAbs were found that stained BaL-infected cells. bnAbs used for ex vivo studies were selected based on breadth of neutralization of B clade virus, and sensitivity and intensity of staining of HIV-infected CD4 T cells. Live CD3 + CD45RO + CD8 - CD14 - CD19 - TCR δγ - CD4 dim and null cells prepared from lymph nodes were stained for expression of PD-1, CD57, CXCR4, CXCR5, CD27 and PGT121 and then bulk sorted into PD-1 + ; PD-1 - CD57 - ; and PD-1 - CD57 + populations. Individual PD1 + cells were index sorted into individual wells, RNA was extracted, purified, and Gag, and Rev- and Tat-associated RNA copy numbers determined by RT PCR. Measureable Tat- and Rev-associated HIV RNA were assumed to represent active transcription of HIV proviral DNA. Results: The highest frequency of CD4 T cells transcribing proviral DNA was found in the PD-1 + , CD4 dim and null population. PD-1 + cells were index sorted and Gag, Tat- and Rev-associated HIV RNAs measured. Ninety-one of 599 (15%) cells sorted from lymph nodes from six untreated, HIV-infected individuals, were actively transcribing HIV RNA. Eighty-five percent of the cells transcribing Tat- and Rev-associated RNA also contained measurable Gag RNA. Staining of HIV envelope by PGT121 was significantly associated with proviral DNA transcription (P<0.0001). Median percentage of PGT121 + CD4 dim and null T cells actively transcribing virus was 41 (range, 12-64)% compared to 17(3-22)% in PGT121 - cells. PGT121 staining was strongly associated with downregulation of CD4 (P<0.0001). A higher percentage of CXCR5 + PD1 + cells actively transcribed proviral DNA than did CXCR5 - PD-1 + cells (P<0.0001). A lesser proportion of CD57 + CD4 T cells, a marker of germinal center cells, actively transcribed proviral DNA than did CD57 - CD4 T cells (P<0.05). Conclusions: Most CD4 T cells transcribing proviral DNA are Tfh cells. Viral transcription occurs both inside and outside of the germinal center in B cell follicles and is identifiable by bnAbs. bnAbs may be a means of targeting HIV-infected CD4 T cells in lymph nodes. 50 Efficacy of HIV-1 Monoclonal Antibody Immunotherapy in Acute SHIV-Infected Macaques Diane L. Bolton 1 ; Amarendra Pegu 2 ; KeyunWang 2 ; Kathleen McGinnis 2 ; Kathryn Foulds 2 ; Srinivas Rao 2 ; Merlin L. Robb 1 ; Nelson L. Michael 1 ; John Mascola 2 ; Richard A. Koup 2 1 US Military HIV Research Program, Silver Spring, MD, US; 2 National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, US Background: Highly potent broadly neutralizing HIV-1 antibodies (bNAb) can suppress viremia in both humanized mouse and macaque models of HIV-1 infection. However, the therapeutic potential of these antibodies during early acute infection (e.g. Fiebig I-III) is unknown. Recent clinical evidence indicates that antiretroviral therapy (ART) administered during this period suppresses both viremia and seeding of the viral reservoir. Here we test the ability of bNAb regimens to control acute simian-human immunodeficiency virus (SHIV) replication in rhesus macaques and compare efficacy to ART. Methods: Rhesus macaques were infected with SHIV-SF162P3 followed by administration 10 days later of either 1) daily triple drug ART; 2) a single dose of Env CD4-binding site specific bNAb, VRC01; 3) a single dose of a combination of a more potent clonal relative of VRC01 (VRC07-523) and a V1/V2 glycan-dependent bNAb (PGT121); or 4) no treatment. Daily ART was initiated 11 days after bNAb. Plasma viremia and cell-associated viral load were measured to assess efficacy. Results: A single infusion of VRC01 on day 10 reduced viremia by ~ 1 log10 over the next 10 days. The combination of VRC07 and PGT121 had a greater effect of between 2 and 3 log10 that was similar to treatment with ART. Following peak viremia, control was better sustained by the dual bNAb and ART regimens than the VRC01 regimen. Plasma bNAb concentrations exceeded IC80 values for at least 7 days in all animals. Proviral DNA in lymph node was also diminished after treatment with ART or dual bNAb, both effecting a ~1 log decline in SHIV copies per CD4 + T cell. Decreased viral replication by these regimens was further evidenced by dampened cellular and humoral immune responses to viral antigens. Greater efficacy of VRC07-523 / PGT121 relative to VRC01 is consistent with more potent neutralization activity of these bNAbs against the SHIV-SF162P3 challenge virus. Conclusions: Our findings demonstrate that potent neutralizing HIV-1-specific antibodies are at least as effective as ART at controlling acute virus replication. Moreover, bNAb immunotherapy may offer an advantage over ART in its ability to further reduce the proviral DNA burden. These data support future therapeutic clinical trials that investigate VRC01, and eventually other antibodies, as an alternative to or in conjunction with ART to treat Fiebig I-III HIV-1 infection. 51 HIV-1 Infections With Multiple Founders Are AssociatedWith Higher Viral Loads Holly Janes 1 ; SodsaiTovanabutra 2 ; Joshua Herbeck 3 ; Supachai Rerks-Ngarm 4 ; Merlin L. Robb 2 ; Nelson L. Michael 2 ; Peter Gilbert 1 ; Jerome H. Kim 2 ; Morgane Rolland 2 The Step/HVTN502 and RV144 study teams 1 Fred Hutchinson Cancer Research Center, University of Washington, Seattle, WA, US; 2 US Military HIV Research Program, Silver Spring, MD, US; 3 University of Washington, Seattle, WA, US; 4 Thai Ministry of Public Health, Bangkok, Thailand Background: A single HIV-1 genetic variant establishes infection in most subjects, including breakthrough infections in the Step/HVTN-502 and RV144 vaccine efficacy trials. We sought to evaluate whether characteristics of the founder viral populations could influence clinical outcomes in the infected participants, specifically whether subjects infected with multiple founder variants would exhibit higher viral loads or lower CD4+ T cell counts. Methods: HIV-1 breakthrough sequences obtained by single genome amplification from plasma samples collected at diagnosis, and follow up clinical data were available from 63 Step/HVTN502 (MSM infected with HIV-1 subtype B) and 100 RV144 (heterosexuals infected with HIV-1 CRF01_AE) participants. Linear regression models were used to relate qualitative (homogeneous/heterogeneous infection) and quantitative ( env diversity measures) viral predictors to clinical post-infection endpoints. Results: Based on data collected up to 1 year post HIV-1 diagnosis, we found that subjects who had been infected with multiple founder viruses had significantly higher mean viral loads (0.37 log 10 higher, p = 0.007 in Step and 0.29 log 10 higher, p = 0.024 in RV144). Higher env diversity in the founder population was also associated with higher mean viral load (0.59 log 10 higher per 10-fold increase in diversity, p ≤ 0.001 in Step and 0.45 log 10 higher per 10-fold increase in diversity, p = 0.011 in RV144). Moreover, in the RV144 cohort, subjects with more diverse HIV-1 founder populations had significantly lower CD4 T cell counts over time (heterogeneity predictor: p = 0.020, env diversity predictor: p = 0.028). Conclusions: We showed that measures of increased HIV-1 diversity in early HIV-1 infection, both qualitative and quantitative, were associated with markers of poorer clinical outcomes. These results illustrate how consequential the first steps of HIV-1 infection are for clinical disease progression and suggest that limiting the number of viral variants establishing HIV-1 infection may be an important goal for HIV-1 preventive and post-infection disease attenuation strategies. The views expressed are those of the authors and should not be construed to represent the positions of the US Army or the Department of Defense.

Oral Abstracts

102

CROI 2015