CROI 2017 Abstract e-Book

Abstract eBook

Poster and Themed Discussion Abstracts

(75% reduction, p<0.0007). Although ADAR1 deaminase activity was detected in cellular genes, direct modification of viral RNAs by ADAR1 was not observed. siADAR1 MDM also showed upregulation of MDA5 (IFIH1), the cytoplasmic sensor of ADAR1-edited RNAs. However, IFIH1 knockdown did not have a significant effect on innate immune function or HIV-1 infection. Further characterization of innate immune pathways in siADAR1 MDM showed enhanced expression of the innate immune RNA sensor RIG-I, increased STAT1- phosphorylation and IRF7 expression, comparable to that observed after LPS or poly I:C treatment in mock-transfected MDM. Conclusion: ADAR1 knockdown in primary macrophages induces innate immune activation that confers resistance to HIV-1 infection. 260LB LIVER INFLAMMATION CORRELATES WITH SIV LEVELS AND IS ONLY PARTLY REVERSED WITH CART Bridget Fisher 1 , Rachel Brown 1 , MatthewWood 1 , Richard Green 2 , Cole Fisher 1 , Michael Gale 2 , Guido Silvestri 3 , Ann Chahroudi 3 , Nichole Klatt 2 , Donald Sodora 1 1 Cntr for Infectious Disease Rsr, Seattle, WA, USA, 2 Univ of Washington, Seattle, WA, USA, 3 Emory Univ, Atlanta, GA, USA Background: Liver disease is a significant contributor to morbidity and mortality during HIV infection, including those receiving combination antiretroviral therapy (cART). The SIV/HIV virus may be directly influencing liver disease/inflammation through the presence of virus, or indirectly by compromising the gut mucosa, thus permitting increased levels of bacteria translocation to the liver. Methods: Liver tissue was acquired from infant and adult rhesus macaques that were uninfected (n=7/4, infant/adult), SIV-infected (n=9/6), or SIV-infected/cART-treated (n=4/6). To evaluate liver inflammation/disease we quantified immune cell levels (microscopy using CD3 and CD68), gene expression (Agilent Microarray and qPCR), bacteria levels (16s DNA qPCR) and SIV levels (qPCR) in livers obtained at necropsy. Results: There was a significant increase in liver macrophage levels during SIV infection (556 SIV+ vs 327 macrophages/mm2 in uninfected), which subsequently decreased following cART treatment. These macrophages likely migrated into the liver as they correlated with inflammatory (CCL3, TNFa) and pro-fibrotic (TGFb) immune mediators. Importantly, this increase in macrophage number and associated inflammation correlated with levels of SIV in the liver (p=<0.0001) and in the plasma (p=0.0014) with liver T cells identified as SIV-infected. In contrast, the levels of 16s bacterial DNA did not correlate with macrophage levels, as bacterial levels were highest in the SIV+cART treated macaques compared to uninfected (p=0.0006). Microarray analysis identified liver transcriptome changes during SIV infection, which included many immune signaling pathways, such the NF-kB, Rig-I-like receptors, and interferon signaling. Further, cART did not fully resolve immune signaling during SIV infection with a number of immune associated pathways (including NF-kB and innate/adaptive immunity) continuing to be significantly upregulated in SIV+cART macaques. Conclusion: These data provide evidence that liver macrophage infiltration and associated inflammation during SIV infection is likely driven by SIV-infected T cells, and not by translocating bacteria. In addition, cART treatment does not fully resolve liver inflammation. These findings provide insight regarding liver disease that is occurring during SIV/HIV infection and cART, and identifies specific immune targets for reducing liver inflammation in HIV-cART individuals. 261 CD57+ CYTOTOXIC CD4+ EFFECTOR T CELLS INCREASE IN CHRONIC HIV INFECTION Chansavath Phetsouphanh 1 , Jodi Meyerowitz 1 , Lyle Murray 1 , Dominique Goedhals 2 , Cloete Van Vuuren 2 , Sarah Fidler 3 , Paul Klenerman 1 , John Frater 1 1 Univ of Oxford, Oxford, UK, 2 Univ of Free State Med Sch, Bloemfontein, South Africa, 3 Imperial Coll London, London, UK

Background: Cytotoxic CD4+ T cells play a prominent role in chronic viral infection, as evidenced by their influence in the containment of EBV and CMV replication. CD4+ CTL clones specific for HIV-1 Nef and Gag (generated from ex vivo perforin expressing CD4+ T cells) are capable of killing HIV-1 infected CD4+ T cells and macrophages. Additionally, HIV-specific cytolytic CD4+ T cell responses in acute HIV infection are predictive of disease progression. There have been minimal studies on this subset in HIV infection. Extracellular markers, specific transcription factors and mechanism of killing are yet to be determined. Whether HIV-specific CD4+ CTL function in collaboration with CD8+T cells is indicative of viral control remains to be investigated. Methods: Cryopreserved PBMCs from participants with Primary HIV infection (PHI)(n=9; SPARTAC trial) and chronic infection (CHI) (n=9; Bloemfontein, South Africa) were analysed. All participants were not receiving antiretroviral therapy at time of sampling. Flow cytometric phenotyping was performed using BD LSRII. Cell sorting was performed on the Beckman Coulter MoFlo. RNA extraction was performed using QIAGEN RNAeasy micro kit. PCR was performed on the ROCHE Light Cycler 480. Results: CD57 (HNK-1 or Leu2) expression on CD4s identifies cytotoxic cells (Fig. 1A). These cells are dramatically increased in CHI (~5-fold, p<0.0001). CD57 expression correlates with cytolytic granules, granzyme B and perforin expression. This is highly evident in both Primary and chronic HIV-infection (Fig. 1B&D). CD57+ CD4+ T cells decrease with 12 months of anti- retroviral therapy in CHI subjects (p<0.0001), as does Granzyme B and perforin levels (Fig. 1C&E). CD57+ CD4 CTL are CD45RO+memory cells that lack CD28 expression. CD57+ CD4 CTL express lower CCR5 mRNA than CD57- and this correlates with protein expression (Fig 1F&G). Conclusion: CD57 is a marker of cytotoxicity on CD4+ T cells, which allows the characterization of this subject in HIV infection. CD4 CTL increase in chronic HIV infection. CD57+CD4+ cells are highly activated expressing both granzyme B and perforin. The maintenance of these cells may be due to the low expression of HIV entry receptor CCR5. It remains to be seen whether CD57+ CD4 CTL are HIV-specific and have the potential to kill HIV-infected MHC class II presenting cells. The frequency and function of these cells in Elite controllers and Post-treatment controllers may identify possible correlates of protection.

Poster and Themed Discussion Abstracts

262 TARGETING LC WITH ANTI-LANGERIN HIV FUSION MONOCLONAL AB PROMOTES TFH DIFFERENTIATION Jérôme Kervevan 1 , Aurélie Chaigneau 1 , Sandy Zurawski 2 , Marion Bonnet 3 , Romain Marlin 4 , Marie-Thérèse Nugeyre 4 , Elisabeth Menu 4 , Gerard Zurawski 2 , Yves Levy 1 , Sylvain Cardinaud 1 1 INSERM, Créteil, France, 2 Baylor Inst for Immunol Rsr, Dallas, TX, USA, 3 Univ of Cardiff, Cardiff, UK, 4 Inst Pasteur, Paris, France Background: A rationale approach for vaccine design is to target HIV-1 antigen to specific receptors on dendritic cells (DCs) via fused monoclonal antibodies (mAb) with the intention to favor antigen presentation and activation of HIV-specific immune responses (Flamar A.L. et al., AIDS, 2013). In mouse and NHP models, targeting of skin LCs with anti- Langerin mAbs fused with HIV (αLC/HIV-Gag) or Flu antigen drives antigen-specific humoral responses (Yao C. et al., J Allergy Clin Immunol, 2015; Epaulard G. et al., J. Immunol.,

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