CROI 2019 Abstract eBook

Abstract eBook

Poster Abstracts

detectable in the TDL possess an intermediate differentiation status (CCR7- CD45RA-CD27+), thereby defining the identity of HIV-specific CD8+ T cells capable of accessing HIV reservoirs in peripheral tissues. Conclusion: Our results demonstrate that not all types of memory CD8+ T cells survey tissues and reveal that cytolytic molecule expression is mostly confined to effector memory HIV-specific CD8+ T cells in blood during steady- state and chronic HIV disease. These data also suggest that the intermediate differentiation status of peripheral blood HIV-specific CD8+ T cells is a marker of tissue recirculation rather than a dysfunctional state as previously assumed. Elvira Couto Jaime 1 , Flor Etcheverry 1 , Constanza Lucero 2 , Yoko Alenyar 3 , Lorna Leal 2 , Irene Fernandez 1 , Yolanda Romero 2 , Manel E. Bargalló 1 , Martin Goetz 2 , Josep Bombi 2 , Maria Pellise 2 , Maria Lopez-Ceron 2 , Montserrat Plana 2 , Nuria Climent 1 , Felipe Garcia 2 1 IDIBAPS, Barcelona, Spain, 2 Hospital Clinic of Barcelona, Barcelona, Spain, 3 Universitat de Barcelona, Barcelona, Spain Background: The disruption of the intestinal mucosa in HIV individuals leads to an increase of bacterial translocation, immune activation and non-AIDS events in HIV infected individuals. Confocal endomicroscopy could help to assess the changes in gut mucosa. The objective of the study was to describe morphological and dynamic findings in patients with HIV infection by direct visualization of the intestinal mucosa with confocal endomicroscopy and correlate these findings with bacterial translocation markers. Methods: Demographic and clinical characteristics, pathological changes of rectal mucosa biopsies, confocal endomicroscopy findings (amount of intramucosal bacteria, amount of fluorescein in the crypt lumen and in lamina propia), microbial translocation (LBP, sCD14 and EndoCAb) and inflammation (TNF-alpha, IL-6, usPCR, DD) in plasma, T-cell and myeloid subsets in rectal biopsy and peripheral blood were analyzed in 10 HIV individuals. A correlation between microbial translocation and other factors was also performed. Results: We recruited 9 men and 1 woman with median age of 37 years, 9 homosexual and 1 heterosexual. The median CD4 nadir and current CD4 was 572 and 767 cells/mm3, respectively. Only 1 out of 10 patients showed fibrosis in rectal epithelium. In most of the biopsies analyzed, mild chronic inflammation was observed (8/10 individuals). Regarding confocal endomicroscopy, the amount of intramucosal bacteria was high and fluorescein in lamina propia was increased in most individuals, suggesting an abnormality of the mucosal barrier. Translocation markers and myeloid subsets in mucosa were associated with changes of gut mucosa assessed by confocal endomicroscopy: a) CD14s and %CD11c+ CD14- cells vs. the amount of fluorescein in lamina propia (Rho=0.73 p=0.015 and Rho= 0.81 p=0.0045, respectively); b) Endocab and %CD83+ cells vs intramucosal bacteria (Rho=0.64 p=0.04 and Rho=-0.68 p=0.029, respectively). In addition, translocation markers were also correlated with markers of inflammation [EndoCAb vs TNF-alpha (Rho=-0.76 p=0.01) and LBP vs TNF-alpha (Rho=0.65 p=0.04)] and T-cell subsets in peripheral blood [LBP vs CD4+(Rho=-0.75 p=0.01), LBP vs CD4+ CD38+ HLA-DR+ (Rho=0.70 p=0.02), and LBP vs CD8+ CD38+ HLA-DR+ (Rho=0.73 p=0.01)]. Conclusion: These data suggest that confocal endomicroscopy could be a good tool to further study gut epithelial damage and microbial translocation in HIV infected patients. Background: Microbial translocation is a significant contributor to chronic immune activation and inflammation in HIV–infected humans. In SIV–infected rhesus macaques (RM), translocation has been demonstrated to occur across the gastrointestinal barrier; however, translocating bacterial taxa are not representative of the gut microbiota, with Proteobacteria appearing to preferentially translocate. To fully characterize translocating bacterial populations, we isolated translocated bacteria from chronically SIV-infected macaques and identified them subsequent to live culture. Methods: Liver, mesenteric lymph node, and spleen samples were taken during necropsy from one uninfected and twenty chronically SIV– or SHIV−infected RM, including some Vancomycin−treated animals. Tissue samples were homogenized and plated on: a) Brain Heart Infusion, b) TSA+Tween 80, and c)

TSA+5% Sheep’s Blood media under aerobic conditions, and d) Brucella Blood and e) CDC Blood media under anaerobic conditions. Isolates were grown for 1−7 days, colonies re−streaked for purity, and identified using MALDI−TOF and 16S rDNA sequencing. Shannon α−diversity was calculated for a) SIV+, b) SIV+ Vancomycin−treated and c) SIV+ or SHIV+ animals (no Vancomycin). Results: Thirty-six species have been identified thus far, 5 Proteobacteria (Enterobacteriaceae), 4 Actinobacteria (50% Actinomycetaceae, 25% Corynebacteriaceae, 25% Coriobacteriaceae), 2 Bacteroidetes (50% Odoribacteraceae, 50% Prevotellaceae) and 25 Firmicutes (32% Lactobacillaceae, 16% Streptococcaceae, 12% Enterococcaceae, 8% Aerococcaceae, 8% Eubacteriaceae, 8% Leuconostocaceae, 4% Bacillaceae, 4% Planococcaceae, 4% Staphylococcaceae, 4% Veillonellaceae). Surprisingly, although our cohort exhibited comparable microbial translocation, α-diversity between tissue sites was significantly reduced in the Vancomycin group as compared to the infected but untreated group with higher levels of Proteobacteria having translocated in Vancomycin-treated animals (two-way paired t-test, p=0.0739). Conclusion: While PCR has been relied upon in previous studies to show the presence of translocated bacteria, this study reveals that several translocated bacteria are replication competent and that dysbiosis could influence the types of bacteria which translocate. It remains to be seen whether reduced diversity in Vancomycin-treated animals is due to a further alteration in taxa crossing the epithelial barrier or a change in selection pressure once they’ve translocated. 203 SYNERGY BETWEEN TH1 AND TH22 IMPAIRS TH17 CELLS RECRUITMENT TO THE GUT ON ART Manon Nayrac 1 , Mary Requena 2 , Claire Loiseau 3 , Maud Mavigner 4 , Fatima L’Faqihi 1 , Nicolas Carrere 2 , Bertrand Suc 2 , Jacques Izopet 2 , Pierre Delobel 2 1 INSERM, Toulouse, France, 2 CHU de Toulouse, Toulouse, France, 3 Australian Institute of Tropical Health and Medicine, Cairns, Australia, 4 Emory Vaccine Center, Atlanta, GA, USA Background: During HIV-1 infection, a deep depletion of Th17 cells occurs early in the gut mucosa. Th22 cells are also initially depleted but appear to be able to efficiently recover on antiretroviral therapy (ART), while Th17 do not. A pro-inflammatory state also promotes Th1 cells recruitment to the gut on ART. Both Th17 and Th22 cells express CCR6 and could thus be recruited through the CCL20-CCR6 axis. However, we previously reported that CCL20 production by enterocytes is impaired in the duodenum on ART. But Th22 cells can alternatively use the CCL28-CCR10 axis to migrate to the gut. We hypothesized that Th1 and Th22 cells synergistically impair CCL20 production by the enterocytes thus preventing Th17 cells recruitment to the gut. Methods: Duodenal biopsies were obtained from 10 HIV-1-infected subjects on ART and 10 healthy controls. Intestinal T cells were isolated and Th1 (CD3+CD4+CXCR3+CCR4-CCR6-), Th17 (CD3+CD4+CXCR3- CCR4+CCR6+CD161+), and Th22 (CD3+CD4+CXCR3-CCR4+CCR6+CD161- CCR10+) cell frequencies were analyzed by flow cytometry (BD Fortessa). A model of primary human intestine epithelial cell culture was used to decipher enterocyte response to cytokines and T cells in co-culture experiments. CCL20 and CCL28 expression was quantified by qRT-PCR (mRNA) and ELISA (protein). Results: The frequency of Th17 cells in the duodenum of treated HIV-1-infected subjects remained lower than in healthy controls (4.3% vs 7.6%, P<0.05). By contrast, Th22 cells were restored to normal values (6.3% vs 5.4%, P=0.53), and Th1 cells were increased (9.0% vs 4.7%, P<0.01) in HIV-1-infected vs healthy controls. Ex-vivo, IFN-γ, the main Th1 cytokine, induced a 5-fold decrease in CCL20 mRNA expression by enterocytes. IFN-γ strongly increased IL-18 production (up to 100-fold), which in turn further decreased CCL20 expression by 2 to 3-fold. IL-22, mainly produced by Th22 cells, induced a 2 to 3-fold decreased in CCL20 expression by enterocytes, and also indirectly contributed to CCL20 inhibition by promoting IL-18 expression. Similarly, co-cultures between enterocytes and Th1 and Th22 cells showed a reduction of CCL20 production by enterocytes. By contrast, CCL28 production was preserved allowing Th22 recruitment through the CCR10 axis in this setting. Conclusion: Th1 and Th22 synergistically blunt CCL20 production by enterocytes through IFN-γ, IL-18, and IL-22, preventing Th17 reconstitution in the gut of HIV-1-infected subjects on ART.

201 MICROBIAL TRANSLOCATION MEASURED BY CONFOCAL ENDOMICROSCOPY IN HIV-INFECTED PATIENTS

Poster Abstracts

202 ISOLATION OF TRANSLOCATING BACTERIA IN PROGRESSIVE SIV INFECTION OF RHESUS MACAQUES Jacob Flynn , Alexandra Ortiz, Jason Brenchley National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA

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CROI 2019