CROI 2016 Abstract eBook

Abstract Listing

Poster Abstracts

Methods: Thirty-three subjects underwent phlebotomy and sigmoid biopsy at the time of AHI diagnosis. AHI was grouped using the fourth generation (4thG) immunoassay (IA) staging, with all stages being HIV RNA+ (Stage I: 4thGIA - /3rdGIA - ; II: 4thGIA + /3rdG - ; III: 4thGIA + /3rdGIA + ). Of the 33 subjects 14 were 4thGI and 19 4thGIII. Multiparameter flow- cytometry was performed to determine the frequency of mucosal CD4 + CCR5 + T cells and the frequency of peripheral β7 high CD4 + T cell subsets at the time of AHI diagnosis. Results: During 4thGI the frequency of mucosal CD4 + CCR5 + T cells and peripheral β7 high CD4 + T cells remained comparable to HIV-uninfected subjects, however with progression of 4thG stage a significant decrease in frequency was observed (Table 1). The frequency of peripheral β7 high CD4 + T cells correlated inversely with plasma (r=-0.52, p<0.001) and sigmoid (r=-0.36, p=0.03) HIV RNA and directly with the loss of mucosal CD4 + CCR5 + T cells (r=0.36, p=0.02). Additionally, we observed a loss of peripheral central memory (CM; CD27 + CD45RO + ) CD4 + T cells expressing CCR5 and β7 high during progression of AHI (Table 1). The frequency of CCR5 + β7 high CM CD4 + T cells showed a strong direct correlation with the loss of mucosal CD4 + CCR5 + T cells (r=0.44, p=0.008) and correlated inversely with plasma HIV RNA (r=-0.51, p=0.002). Conclusions: The loss of peripheral β7 high CD4 + and CCR5 + β7 high CM CD4+ T cell subsets closely paralleled the loss of mucosal CD4 + CCR5 + T cells during early AHI. This is consistent with the hypothesis that α4β7 has a role in the selective depletion of mucosal CD4 + T cells, and indicates that monitoring β7 high expression on peripheral blood CD4 + T cells could be a useful surrogate marker to estimate mucosal CD4 + CCR5 + T cell loss.

288 HIV Infections in Novel CD1a Cells FromHuman Vaginal Mucosa Victor Pena-Cruz 1 ; Luis Agosto 2 ; Hisashi Akiyama 2 ; Jean-Robert Larrieux 3 ; Rahm Gummuluru 2 ; Manish Sagar 1 1 Boston Univ, Boston, MA, USA; 2 Boston Univ Sch of Med, Boston, MA, USA; 3 Boston Med Cntr, Boston, MA, USA Background: Transfer across mucosal surfaces, such as the vaginal mucosa, account for the majority of new HIV-1 infections in the world. The identity and susceptibility of potential target cells in the vaginal mucosa remain unclear. Methods: Skin and vaginal cells were obtained fromwomen undergoing elective reduction mammoplasties and vaginal repairs respectively. Discontinuous density gradients were used to isolate epithelial and subepithelial cells, and anti-human CD1a magnetic beads were used to further purify the epithelial cells. Isolated cells were characterized using flow cytometry, electron-microscopy (EM) and Western blotting. Ability of different CCR5 (R5) or CXCR4-using (X4) HIV-1 to fuse, integrate, and replicate in these cells was examined by using the BlaM-Vpr fusion assay, Alu-PCR integration, and growth curves respectively. Results: Similar to skin derived Langerhans cells (LCs), vaginal epithelium based cells expressed CD1a, CD1c and langerin but not DC-SIGN or CD14. In contrast to skin LCs, vaginal epithelial cells, termed CD1a+ VDCs, either contained low numbers or no Birbeck Granules, a hallmark of all LCs. HIV-1 YU-2 (R5) but not NL4-3 (X4) replicated in CD1a+ VDCs. The CD1a+ VDCs expressed the CXCR4 receptor, and NL4-3 both fused and integrated in the CD1a+ VDCs. Vaginal subepithelial tissue resident lymphocytes were CD69+ and displayed a memory phenotype. Both YU-2 and NL4-3 replicated in vaginal lymphocyte cultures. Interestingly, both NL4-3 and YU-2 replicated in CD1a+ VDCs exposed to virus, washed and co-incubated with vaginal sub-epithelial lymphocytes 3 days post-exposure. Conclusions: CD1a+ VDCs differentially support replication of CCR5- but not CXCR4-using HIV-1. These unique CD1a+ VDCs are located at the portal of virus entry and are only susceptible to types of HIV-1 strains that initiate most infections, which suggests that CD1a+ VDCs are likely the earliest target cells for HIV-1 in the vaginal mucosa. 289 Influx of Th1 Cells in the Gut Mucosa Impairs the Homing of Th17 Cells Under cART Claire Loiseau 1 ; Mary Requena 2 ; Michelle Cazabat 2 ; Nicolas Carrere 2 ; Bertrand Suc 2 ; Bruno Marchou 2 ; Jacques Izopet 2 ; Pierre Delobel 2 1 INSERM 1043, Toulouse, France; 2 CHU Toulouse, Toulouse, France Background: During HIV-1 infection, the integrity of the intestinal immune barrier is disrupted due to a deep depletion of CD4 + T cells in the gut, including Th17 cells, a T cell subset exerting a major role in antimicrobial immunity. Th17 cells traffick to the gut mainly along the CCR6-CCL20 axis. We previously established that despite effective cART, Th17 cells homing to the small intestine mucosa is altered due to a reduced CCL20 production by enterocytes. A regulating loop occurs between IL-17 secretion, CCL20 production, and Th17 cells gut homing. The persistence of various inflammatory stimuli in the gut mucosa despite cART could contribute to a disequilibrium in the gut mucosa homeostasis. We thus assessed how Th1 cells could influence the homing of Th17 to the gut along the CCR6-CCL20 axis in this setting. Methods: Duodeno-jejunal biopsies were obtained by endoscopy in 10 HIV-1-infected individuals and uninfected controls. HIV-1-infected individuals had plasma HIV-1 RNA <50 copies/mL under cART for about 5 years. Their median blood CD4 + T cells count was of 668 cells/µL. Gut Th1 cells frequency was evaluated by flow cytometry and CXCR3 + cells frequency was determined by immunohistochemistry. The effect of IL-2 and IFN-γ on CCL20 expression was assessed in an ex-vivo model of human primary enterocytes cultured as a tight monolayer on transwells. To explore the impact of Th1 cells on CCL20 production, cocultures were done between the enterocytes and various proportions of Th1 and Th17 cells placed in the bottom chamber of the transwells to mimic lamina propria -epithelium interactions. Th1 and Th17 cells were sorted from PBMCs by flow cytometry on the basis of their CD3 + CD4 + CXCR3 + CCR4 - CCR6 - and CD3 + CD4 + CXCR3 - CCR4 + CCR6 + CD161 + phenotype respectively . The expression of CCL20 by the enterocytes was evaluated by qRT-PCR and ELISA. Results: In small intestine mucosa of HIV-1-infected individuals under effective cART, Th1 and CXCR3 + cells frequencies were significantly increased compared to uninfected controls ( P <0.05). Ex-vivo on human primary enterocytes, both IL-2 and IFN-γ decrease CCL20 expression, by 2-fold and 6-fold, respectively. In coculture experiments, CCL20 expression decreases as the Th1/Th17 ratio skews from Th17 to Th1 cells. Conclusions: An influx of Th1 cells in the lamina propria of HIV-1-infected individuals despite effective cART could contribute to the reduced production of CCL20 by the enterocytes, then blunting the homing of Th17 cells to the gut. 290 Reduced Rectal HIV RNA After Peg-IFN-a2b Added to ART Together With ART Interruption Emmanouil Papasavvas 1 ; Guobin Kang 2 ; Livio Azzoni 1 ; Faten Aberra 3 ; PabloTebas 3 ; KaramMounzer 4 ; Jay R. Kostman 5 ; Douglas D. Richman 6 ; Qingsheng Li 7 ; Luis J. Montaner 1 1 The Wistar Inst, Philadelphia, PA, USA; 2 Univ of Nebraska, Lincoln, NE, USA; 3 Univ of Pennsylvania, Philadelphia, PA, USA; 4 Jonathan Lax Immune Disorders Treatment Cntr, Philadelphia, PA, USA; 5 John Bell Hlth Cntr, Philadelphia, PA, USA; 6 Univ of California San Diego, San Diego, CA, USA; 7 Sch of Biological Scis and Nebraska Cntr for Virology, Univ of Nebraska, Lincoln, NE, USA Background: The effects of Peg-IFN-a2b immunotherapy on gut tissue HIV-1 RNA remain unknown. We hypothesized that in antiretroviral therapy (ART) chronically suppressed HIV-1 + individuals addition of Peg-IFN-a2b to ART, including of a short ART interruption (to induce HIV reactivation), would decrease rectal tissue HIV levels by triggering anti-HIV mechanisms. Methods: 20 ART chronically suppressed (<50 copies/ml) HIV-1 + subjects received 20 weeks of Peg-IFN-a2b. ART was continued for the first 5 weeks, followed by a 4-week interruption, and resumption fromweek 9-20. Viral load (VL) and CD4 + T cell levels were monitored throughout the treatment. Parameters assessed at baseline (BL) and after 20 weeks of treatment (EoT) included: a) immune activation markers (e.g. CD38, CD69, NKG2A, NKG2C, KIR) and IFN-responsive molecules (e.g. CD169, Tetherin) on cryopreserved

Poster Abstracts

111

CROI 2016