CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

Background: Identification of specific, cell-surface markers of residual HIV infection is a top research priority. We studied CD30 (TNF superfamily receptor) and CD32 expression in blood and gut-associated lymphoid tissue (GALT), determined the HIV burden within CD4+ T cells expressing these markers, and evaluated response to ex vivo anti-CD30 therapy. Methods: CD4+ T cells from blood or gut tissue were sorted based on expression of CD30 and CD32 followed by quantification of cell-associated HIV-1 DNA and RNA. In situ HIV RNA hybridization studies were performed on GALT, and PBMC from ART-suppressed individuals were co-cultured in the presence of the cytotoxic antibody-drug-conjugate, brentuximab vedotin, an approved cancer therapy that targets CD30. Results: Overall, the frequency of CD30 expressing peripheral CD4+ T cells was significantly higher in ART suppressed (n=17; P=0.002) and viremic (N=9; P=0.045) individuals compared to HIV-uninfected controls. CD30+ T cells expressed higher levels of HLA-DR, CD69 and PD1, although very few activated CD4+ T cells expressed CD30. Cell-associated HIV-1 RNA was significantly enriched in CD30 expressing peripheral CD4+ T cells from ART suppressed (n=17; P=0.008) and viremic participants (n=9; P=0.007). Despite the rarity of CD30+ T cells (<4% of CD4+ T cells), an average of 21% and 28% of HIV-1 RNA burden was attributed to CD30+ cells in suppressed and viremic groups. >90% of detectable cell-associated HIV-1 RNA was found within CD30+CD4+ T cells in samples from 5 individuals, and >50% of cell-associated HIV-1 DNA was attributed to CD30+CD4+ T cells from 3 participants on ART. Interestingly, HLA-DR expression in gut CD4+ T cells was highest in dual CD30+CD32+ expressing cells. Despite the finding that only 0.1% of GALT cells expressed CD30+ RNA determined by in situ hybridization, 88% of all HIV-1 RNA+ cells from ART-suppressed participants expressed CD30 RNA. 78% of HIV RNA+ GALT cells from suppressed individuals expressed CD32, but 80% of GALT cells expressed CD32 in uninfected controls. Finally, ex vivo treatment with brentuximab vedotin, significantly reduced the mean level of HIV-1 DNA in PBMC obtained from seven ART-suppressed individuals (Figure 1). Conclusion: Our results suggest that CD30+ expression appears to be a marker of residual HIV-1 transcriptional activity in the setting of suppressive ART and that targeting CD4+ T cells from ART-suppressed individuals may reduce overall HIV DNA burden.

expression and recognition, HIV antibody (Ab) and T cell responses may correlate with measures of HIV persistence. Methods: Plasma and PBMC samples were obtained from 100 individuals on suppressive ART in the ACTG A5321 cohort. Cell-associated (CA) HIV DNA and unspliced RNA levels (using qPCR targeting pol) and Ab concentrations and avidity to Env/p24 (using LS-VITROS and Avidity Vitros assays, respectively) were measured longitudinally at yr 1, 4 and (for some participants) yr 6-15 after ART initiation. Plasma HIV RNA by single copy assay and T cell responses (IFN-γ ELISPOT) against Gag, Pol, Env, Nef/Tat/Rev, Vpr/Vpu/Vif were measured at the last time point (yr 4-15; median 7 yr of ART). Results: HIV Ab levels and avidity declined with increasing time on ART and were positively associated with HIV DNA at yr 1, 4 and 4-15 of ART (r=0.35 and 0.38, respectively, p<0.001 at the last time point). Nef/Tat/Rev-specific T cell responses, but not responses against other gene products, correlated with HIV DNA levels (r = 0.23, p = 0.03). Neither Ab levels nor T cell responses correlated with cell-associated HIV RNA or plasma RNA by single copy assay. HIV Ab and avidity correlated with T cell responses to HIV Pol (r=0.3, p=0.01 and r =0.26, p=0.04, respectively) and to Nef/Tat/Rev (r =0.35; p =0.005 and r =0.39, p=0.001). There were no correlations between HIV Ab measures and T cell responses to HIV Gag or Env, or to CMV and EBV controls. Conclusion: In individuals on long-term ART, HIV-specific Ab to ENV/p24 and T cell responses to Nef/Tat/Rev correlate with each other and with HIV DNA levels but not with CA HIV RNA or residual plasma viremia. These findings suggest that the total frequency of HIV-infected cells (HIV DNA) may be a better marker of antigen expression that drives immune responses on ART than CA RNA in blood or residual viremia, which reflect activity of only a small fraction of proviruses that can be induced to express antigen. The positive correlation between HIV immune responses and HIV DNA suggests that the immune system is sensing, but not clearing, infected cells, perhaps because of immune dysfunction. Sensing of infected cells by immune responses suggests that tracking these measures may be a method of assessing the impact of reservoir reducing strategies. 393 BLINDED EVALUATION OF ULTRASENSITIVE ASSAYS OF HIV IN PLASMA Sheila M. Keating 1 , Mars Stone 1 , Xutao Deng 1 , Sonia Bakkour 1 , John W. Mellors 2 , Douglas D. Richman 3 , Rob Gorelick 4 , Jeffrey D. Lifson 4 , Cheryl Jennings 5 , Martin Stengelin 6 , Guoxin Wu 7 , Bonnie J. Howell 7 , Peter Bacchetti 8 , Michael P. Busch 1 1 Blood Systems Research Institute, San Francisco, CA, USA, 2 University of Pittsburgh, Pittsburgh, PA, USA, 3 University of California San Diego, La Jolla, CA, USA, 4 Leidos Biomedical Research, Inc, Frederick, MD, USA, 5 Rush University Medical Center, Chicago, IL, USA, 6 Meso Scale Diagnostics, LLC, Rockville, MD, USA, 7 Merck & Co, Inc, West Point, PA, USA, 8 University of California San Francisco, San Francisco, CA, USA Background: A major barrier to developing HIV cure interventions is the lack of validated assays that reliably quantify HIV in plasma below the limit of detection of current clinical assays. We sought to objectively assess the performance characteristics of newer, more sensitive assays to quantify plasma viremia. Methods: The HIV Reservoir Assay Validation and Evaluation Network (RAVEN) project was created to assess the sensitivity, specificity, limits of detection and quantitative ranges of blood-based assays of HIV persistence. To accomplish this for HIV detection in plasma, blinded 50-sample panels containing subtype B and C HIV including duplicate, virus-spiked analytic standards (2 subtype- specific 5-step, 3-fold dilution series with highest concentrations ranging from 45 to 6 copies/mL to lowest concentrations ranging from 0.33 to 0.07 copies/ mL), clinical samples with expected low-level viremia and negative controls were distributed to 8 laboratories for HIV quantification using 9 assays. Four assays included centrifugation to concentrate virus prior to HIV RNA nucleic acid extraction and PCR amplification; two included replicate testing using diagnostic HIV RNA assay platforms; while two utilized ultrasensitive detection of p24 Ag without virus enrichment. Results were analyzed for sensitivity, specificity, reproducibility, and ability to accurately quantify HIV in standards. Results: Data from five laboratories using 6 assays were included in this analysis. Four of five RNA-amplification based assays detected virus in the standards down to ~1 copy/mL in at least 1 of the 2 replicates; negative controls were all negative. All RNA-amplification-based assays had strong correlations between replicates across the standards (p<0.05, rho>0.8). Four assays quantified standards with little bias (mean recovery 69-218% of nominal HIV [RNA]) whereas one assay overestimated copies/mL by >300%. Ultrasensitive p24 Ag assays were not able to quantitatively measure HIV in the diluted

Poster Abstracts

392 HIV ANTIBODY AND T CELL RESPONSES ON ART ARE ASSOCIATED WITH HIV DNA BUT NOT RNA Sheila M. Keating 1 , R. Brad Jones 2 , Christina Lalama 3 , Ronald Bosch 3 , Deborah McMahon 4 , Dylan Hampton 1 , Evelyn Hogg 5 , Joshua C. Cyktor 4 , Joseph J. Eron 6 , John W. Mellors 4 , Michael P. Busch 1 , Rajesh T. Gandhi 7 1 Blood Systems Research Institute, San Francisco, CA, USA, 2 The George Washington University, Washington, DC, USA, 3 Harvard University, Boston, MA, USA, 4 University of Pittsburgh, Pittsburgh, PA, USA, 5 Social &Scientific Systems, Silver Spring, MD, USA, 6 University of North Carolina Chapel Hill, Chapel Hill, NC, USA, 7 Massachusetts General Hospital, Boston, MA, USA Background: HIV-specific immune responses decline after initiation of antiretroviral therapy (ART). Infected cells that persist during ART are thought to be invisible to the immune system, but if there is intermittent antigen

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