CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

Conclusion: HIV exploits the IC regulatory mechanism of T cell activation and function to favor persistence of HIV transcription/production in treated aviremic HIV-infected subjects. It also indicates that an imbalance in IC/IC-L interactions is a novel mechanism contributing to HIV persistence in germinal centers. 382 CELLULAR PROLIFERATION MAINTAINS GENETICALLY INTACT AND DEFECTIVE HIV-1 OVER TIME Bethany A. Horsburgh 1 , Bonnie Hiener 1 , John-Sebastian Eden 1 , Eunok Lee 1 , Timothy E. Schlub 2 , Susanne von Stockenstrom 3 , Lina Odevall 3 , Jeffery Milush 4 , Teri Liegler 4 , Rebecca Hoh 4 , Rémi Fromentin 5 , Nicolas Chomont 5 , Steven G. Deeks 4 , Frederick M. Hecht 4 , Sarah Palmer 1 1 The Westmead Institute for Medical Research, Westmead, NSW, Australia, 2 University of Sydney, Camperdown, NSW, Australia, 3 Karolinska Institute, Stockholm, Sweden, 4 University of California San Francisco, San Francisco, CA, USA, 5 Université de Montréal, Montreal, QC, Canada Background: A thorough understanding of the cellular mechanisms maintaining replication-competent virus will be needed to design future HIV eradication therapies. We examined the relative proportions of genetically identical intact and defective proviruses within memory CD4+ T cell subsets from individuals on prolonged ART. Methods: Naïve, central (CM), transitional (TM) and effector (EM) memory CD4+ T cells, as well as CD45RA-HLA-DR+ and CD45RA-HLA-DR- CD4+ T cells, were sorted from the peripheral blood of eight participants on long-term ART. Additional sequences from four participants were obtained four years later. We used the full-length individual proviral sequencing assay, which amplifies single HIV proviruses followed by next-generation sequencing, to characterise proviruses as intact or defective (containing insertion, deletion, stop codons or hypermutation). Duplicated sequences were classified as ≥2 identical HIV DNA sequences. Results: At the early time-point, 1041 sequences were obtained, and only 4%were considered intact. The proportion of intact proviruses was different across cell subsets (p<0.001), with the highest proportion observed in EM and HLA-DR+ cells. Equivalent amounts of duplicated sequences were identified in defective and intact proviruses. However, when stratified by treatment duration, the proportion of duplicated sequences was higher in those on therapy for >14 years. Of note, no intact duplicated sequences were observed in participants on therapy for <5 years. Duplicated intact sequences were predominantly found in EM and HLA-DR+ cells; representing 24% and 17% of all intact sequences in these subsets respectively. These intact duplicated sequences were observed in two participants four years later. In one participant where no intact provirus was observed, a large expansion of defective sequences predominated (28/68 sequences; 41%). These defective sequences expanded four years later, representing 78% of all sequences isolated (167/215 sequences). Conclusion: Cellular proliferation contributes to the expansion of both genetically intact and defective proviruses. Expansions of defective proviruses may dilute the number of intact proviruses and therefore lead to difficulty in their identification in some participants. Notably, genetically identical intact proviruses are enriched in HLA-DR+ and EM cells and these proviruses are stable over time, indicating the latent HIV reservoir is maintained in these T cell subsets in the peripheral blood by proliferation. 383 INCREASED NUMBERS OF INTACT HIV SEQUENCES IN Α4Β7 T CELLS DURING ACUTE SEROCONVERSION Sofie L. Rutsaert 1 , Pilar Garcia Broncano 2 , Marie-Angélique D. De Scheerder 1 , Basiel Cole 1 , Mathias Lichterfeld 2 , Linos Vandekerckhove 1 1 HIV Cure Research Center, Ghent University, Ghent, Belgium, 2 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA Background: Memory CD4 T cells expressing the integrin α4β7 seem highly susceptible to HIV-1 infection, and may represent a preferential site for viral infection and reservoir establishment. Recent studies suggested that when used in combination with regular antiretroviral therapy during acute SIV infection, monoclonal antibodies blocking α4β7 may enable rhesus macaques to control viremia after ART discontinuation. In contrast, a clinical trial with α4β7 blocking antibodies in humans with chronic HIV-1 infection has recently been completed, without markedly increased frequencies of individuals achieving post-treatment control. Methods: PBMCs were isolated from HIV-1 positive patients (n=4) during acute seroconversion before ART initiation (Fiebig stage III-V). CD4 T cells were

enriched by negative MACS selection, and the α4β7-positive and β7-negative memory CD4 T cell populations were sorted by FACS. Near-full-length, single- genome HIV-1 DNA sequencing of total CD4 T cells, β7-positive and β7-negative CD4 T cell subsets was performed, as described previously. Phylogenetic associations were determined using sequence alignments by MUSCLE and tree building by Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Results: In three out of four patients analyzed at acute seroconversion, the number of HIV-1 DNA copies (intact and defective combined) was higher in the β7-positive cells compared to β7-negative and total CD4 T cells (mean of 897, 186 and 117 total HIV-1 copies/million cells, respectively). The frequency of intact HIV-1 proviruses was also highest in the β7-positive compartment relative to the other two cell populations (mean of 558 versus 99 and 72 intact HIV-1 copies/million cells, respectively). The patient without an HIV-1 enrichment in the β7-positive subset presented with a very high peak viral load (> 7 log copies/mL), low CD4 nadir count below 100 cells/mm3 and CD4 T cells skewed towards a memory phenotype. Phylogenetic analysis of the intact proviral sequences showed that these viruses intermingle between the three different subsets and suggests absence of compartmentalization within the analyzed cell populations. Conclusion: This study suggests that α4β7 memory CD4 T cells represent a primary target site for viral replication during the earliest stages of HIV-1 infection, and raise the possibility that administration of α4β7 antibodies during acute HIV-1 infection may reduce viral reservoir establishment.

Poster Abstracts

384 SEX AND OBESITY ARE ASSOCIATED WITH RESIDUAL VIREMIA IN ART- SUPPRESSED INDIVIDUALS Joshua C. Cyktor 1 , Hanna Mar 2 , Ann Collier 3 , Evelyn Hogg 4 , Catherine Godfrey 5 , Joseph J. Eron 6 , Ronald Bosch 2 , Deborah McMahon 1 , John W. Mellors 1 , Rajesh T. Gandhi 7 , for the A5321 Team 1 University of Pittsburgh, Pittsburgh, PA, USA, 2 Harvard University, Boston, MA, USA, 3 University of Washington, Seattle, WA, USA, 4 Social & Scientific Systems, Silver Spring, MD, USA, 5 DAIDS, NIAID, Bethesda, MD, USA, 6 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 7 Massachusetts General Hospital, Boston, MA, USA Background: The sex of an individual influences HIV levels prior to antiretroviral therapy (ART) and adipose tissue has been proposed to harbor part of the HIV reservoir. The effect of host characteristics, including sex and body-mass index (BMI), on HIV persistence during ART remains incompletely understood. We evaluated factors associated with HIV persistence in a cohort of people with long-term virologic suppression (ACTG A5321). Methods: Participants who initiated ART during chronic infection with sustained virologic suppression had measurements of plasma HIV RNA by single copy assay (SCA), cell-associated HIV DNA and RNA (CA-DNA, CA-RNA). We assessed the effect of age, sex (reported at birth), BMI, waist circumference

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