CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

from SIV/SHIV-infected Rhesus macaques (RM) exhibit increased endothelial dysfunction and infiltration of CD8 T cells, and that there is an expansion of activated CD8 T cells that express the vascular endothelium-homing fractalkine receptor CX3CR1 in ART-treated HIV infection. Here we measured IL-15 and fractalkine (CX3CL1) in the aortic endothelium of SIV/SHIV-infected RM and hypothesize that endothelial-T cell interactions promote the activation and trafficking of CD8 T cells to sites of endothelial cell (EC) dysfunction. Methods: Paraffin embedded descending thoracic aortas from 17 SHIVSF162P3 or SIVmac239 infected and 17 uninfected RM were used for immunofluorescence staining for CX3CL1 or IL-15 and imaged by epifluorescent microscopy. Expression of CX3CL1 and IL-15 was measured in primary human aortic ECs and supernatant by imaging, real-time PCR, and ELISA. Chemotaxis of purified T cells across 3μm collagen-coated transwells was assessed. Purified T cells were treated with recombinant IL-15 (20ng/ml) for 2 or 7 days and analyzed by flow cytometry. Results: ECs exhibited gene expression, surface localization, and secretion of both CX3CL1 and IL-15 in vitro. CX3CL1 (P=0.005) and IL-15 (P=0.045) expression was significantly increased in the aortic endothelium of RM when compared to levels among uninfected control aortas. CD8 T cells showed increased migration through the transwell membrane toward cultured ECs compared to medium control. IL-15 increased T cell expression of the cytolytic molecules granzyme B and perforin (P=0.039) and also increased surface expression of the tissue-residence receptor CD69 (P=0.016) on CX3CR1+ CD8 T cells (n=8). IL-15 also increased both the percentage of CD8 T cells expressing CX3CR1 (P=0.01) and CX3CR1 density (P=0.002). Conclusion: Here we show elevated expression of CX3CL1 and IL-15 in SIV/ SHIV-infected rhesus vascular endothelium. We demonstrated that ECs can produce CX3CL1 and IL-15 in vitro and enhance CD8 T cell migration. IL-15 promotes cytolytic potential of CD8 T cells and increases their expression of CX3CR1, suggesting that in the setting of HIV infection, an altered endothelium tethers, activates and promotes tissue retention of CD8 T cells that can contribute to vascular dysfunction and damage. 242 SMOKING INHIBITS HIV-1 INDUCED CD8+ T CELL INFILTRATION INTO THE ALVEOLAR SPACE Bjorn Corleis 1 , Josalyn Cho 2 , Samantha J. Gates 1 , Antonella C. Lisanti 1 , Puja Kohli 2 , Amy K. Dickey 1 , Abigail Schiff 1 , Scott R. Harris 2 , Benjamin Medoff 2 , Douglas Kwon 1 1 Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA, 2 Massachusetts General Hospital, Boston, MA, USA Background: HIV-1 infection results in inflammation in the lung and a CD8+ T cell alveolitis. This inflammation is only partially reversed by antiretroviral therapy (ART) and is thought to contribute to an increased risk of chronic obstructive pulmonary disease (COPD) in those living with HIV. Smoking is the single greatest risk factor for development of COPD and is closely associated with CD8+ T cell accumulation in lung tissue. Although 70% of HIV-infected individuals smoke, the lung immune response against HIV-1 in the context of smoking has not been well characterized. Methods: HIV-infected subjects on ART who were current- and never- smokers underwent bronchoscopy with bronchoalveolar lavage (BAL) and airway brushing. Lung and blood immune cells were analyzed using flow cytometry and mass cytometry by time-of-flight (CyTOF). Monocyte derived macrophages (MDMs) were exposed to cigarette smoking extract (CSE) in vitro and chemotactic attraction of T cells was investigated in a transwell assay. Chemokines in the BAL fluid were measured by Luminex. Results: We found an HIV-associated increase in the number of CD8+ effector memory T cells in the blood and BAL fluid of never smokers. These CD8+ T cells demonstrated increased expression of the lung homing receptor CXCR3. Among HIV-infected smokers, however, this increase in BAL CD8+ T cells was not observed and there was a corresponding decrease in levels of the CXCR3 ligand CXCL10 in the BAL fluid. However, HIV-infected smokers had an increased frequency of CD69-CD103-non-residenttissue CD8+ T cells in bronchial brushings, suggesting impaired trafficking from circulation into the airspaces. In vitro CSE exposure of MDMs resulted in decreased CXCL10 production and reduced MDM-mediated recruitment of CD8+ T cells in a transwell assay. Blocking CXCL10 signaling with an antibody against its receptor, CXCR3, abrogated CD8+ T cell recruitment by MDMs. Conclusion: In conclusion, HIV-infected subjects on ART have ongoing recruitment of CD8+ T cells to the airways. Smoking blocks production of

the T cell recruiting chemokine CXCL10 in macrophages, which inhibits HIV-1 induced CD8+ T cell recruitment to the airspaces. This may then result in the accumulation of CD8+ T cells in the lung parenchyma, which has been associated with the development of COPD. Our data propose a potential mechanism for the disproportionate risk of COPD observed in smokers living with HIV. 243 INCREASES IN TH17 CELL DENSITY AT MUCOSAL SURFACES IN STATES OF ELEVATED PROGESTINS Megan Halkett , Ann M. Carias, Thomas Hope Northwestern University, Chicago, IL, USA Background: Male to female sexual transmission of HIV contributes to the majority of new infections. There are several known risk factors that increase a woman’s chance of acquiring HIV: unprotected sex with an HIV+male, with IV drug users, with many and/or anonymous partners, as well as previous infection with another STI. An additional risk factor may be high levels of progestins, both exogenous and endogenous. In order to understand a woman’s relative risk of infection during times of high progesterone levels, we characterized the changes to HIV target cell populations in the female reproductive tract in response to increased progestins. Th17 cells were the focus of this project as they have been identified as preferentially infected by HIV. Methods: Eight female pigtail macaques were sacrificed at different phases of the menstrual cycle with vaginal and cervical tissues frozen in OCT. An additional seven rhesus macaques were either treated or not treated with DMPA and tissues were processed in the same manner. Tissues were sectioned and stained for CD3, CD4, CCR6 and DAPI. Deconvolution fluorescence microscopy was used to image the tissue epithelia to identify and phenotype with cell densities determined by cell count per area of epithelium in each image. Th17 cells were defined as cells that are triple positive for CD3, CD4 and CCR6. Results: High levels of both endogenous and exogenous progestin were associated with a greater density of intraepithelial CD4+ target cells. This trend was also observed in the highly susceptible subset of the CD4+ target cell population, Th17 cells. The increased infiltration of vulnerable immune cells at the mucosal surface increases the availability of target cells to SIV/HIV virions, thus increasing the risk of acquisition. Conclusion: High progesterone states are a risk factor for increased sexual acquisition of HIV in women. Increased levels of progestins, exogenous or endogenous, result in an increased infiltration of SIV/HIV target cells, particularly Th17 cells, into the epithelium. A greater presence of target cells at this vulnerable mucosal surface increases the probability of interaction with a SIV/HIV virion and subsequent infection. 244 IDENTIFICATION OF NK CELL SUBSETS CORRELATING WITH HIV DNA IN HIV-INFECTED SUBJECTS Christopher Pohlmeyer 1 , Veronica Gonzalez 2 , Alivelu Irrinki 1 , Ricardo Ramirez 1 , Li Li 1 , Andrew Mulato 1 , Jeffrey Murry 1 , Aaron Arvey 1 , Rebecca Hoh 3 , Steven G. Deeks 3 , Garry Nolan 2 , George Kukolj 1 , Tomas Cihlar 1 , Stefan Pflanz 1 , Gundula Min-Oo 1 1 Gilead Sciences, Inc, Foster City, CA, USA, 2 Stanford University, Stanford, CA, USA, 3 University of California San Francisco, San Francisco, CA, USA Background: The mechanism of natural immunological control of HIV infection has not been fully elucidated. We characterized NK cells from various populations of HIV-infected subjects to identify novel, non-T cell populations associated with control. Methods: We used mass cytometry to measure the expression of 25 NK cell surface markers on cells from elite controllers (EC n=13), viremic controllers (VC n=27), non-controllers on suppressive ART (NC n=21), viremic non-controllers (VNC n=12), and seronegative healthy donors (HD n=20). We also quantified total HIV DNA levels in PBMCs as a measure of viral reservoir. We performed linear regression analysis across all subject groups to identify NK cell markers in two primary NK subsets (CD56 bright CD16 - , CD56 dim CD16 + ) and ‘anergic’ NK cells (CD56 - CD16 + CD7 + ) that correlate with clinical parameters, virus control, and reservoir size. Finally, we assessed NK cell marker repertoire diversity by Simpson’s index. Results: For subjects with detectable viral load, HIV DNA strongly correlated with detectable plasma viremia (p=0.0004). HIV DNA reservoir negatively correlated with Siglec-7 expression on both CD56 dim CD16 + and CD56 - CD16 + CD7 + cells (p=0.011 and 0.026, respectively). A strong positive correlation was observed between HIV DNA and CD62L expression on CD56 dim CD16 + cells

Poster Abstracts

85

CROI 2018