CROI 2018 Abstract eBook

Abstract eBook

Poster Abstracts

Methods: Frozen matched peripheral blood mononuclear cells (PBMC) and lymph node (LN) cells of 29 acute HIV-infected Thais (wk.0), 29 antiretroviral therapy (ART)-treated, chronically infected and uninfected Thais (n=13) were studied. The immune cells of CD4, CD8 and B cells were characterized by flow cytometry. Results: Frequencies of resting memory (RM) B cells (CD21+CD27+IgG+CD20+) were significantly decreased whereas frequencies of tissue-like memory (TLM) B cells (CD21-CD27-IgG+CD20+) were significantly increased during AHI in PBMC but not in LN. However, frequencies of RM and TLM B cells were not restored as the same level in healthy donors after ART. Frequencies of plasmablast (IgD-CD38hiCD20+) B cells were evaluated in PBMC at all AHI stages but not in LN. Importantly, in LN, frequencies of CD4 Tfh cells (CXCR3-PD1+CXCR5+CD45RA-CD4+) were not elevated compared to controls and significantly lower than in chronic infection except for a transient increase at Fiebig 2 (Fig.1a), suggesting that CD4 Tfh cells are depleted or not generated in AHI after Fiebig 2 impacting B cell maturation. Germinal Center (GC) B cells (CD38++IgD-) showed a similar transient increase in Fiebig 2 in LN that did not persist in later AHI stages (Fig.1b) suggesting that GC formation is impaired in AHI. Interestingly, frequencies of CD4 Tfh cells were associated with frequencies of GC B cells (p=0.0009) (Fig.1c). Moreover, both CD4 and CD8 T cell subsets showed activated effector (Ki67+Bcl-2lo) cells as early as Fiebig 1 in PBMC and Fiebig 2 in LN followed by an increase in later stages of AHI in both compartments. Interestingly, frequencies of effector CD4 and CD8 T cells and HIV-specific CD8 T cells correlated between PBMC and LN. In contrast, other immune subsets exhibited decreasing frequencies in blood during AHI while remaining stable in LN. Conclusion: The phenotypes of immune cells are unique in blood vs. LN. Understanding the immune cells alteration in these compartments during AHI may help defining the mechanisms leading to lack of immune control in natural HIV infection. 286 CYTOLYTIC CD4+ T CELLS WITH FOLLICULAR HOMING PROPERTIES IN CHRONIC HIV INFECTION Enrico Richter 1 , Johanna Eberhard 2 , Marek Korencak 1 , Bruce T. Schultz 1 , Britta Flach 1 , Stefan Esser 3 , Julian Schulze zur Wiesch 2 , Hendrik Streeck 1 1 Institute for HIV Research, Essen, Germany, 2 University Hospital Hamburg– Eppendorf, Hamburg, Germany, 3 University Hospital Essen, Essen, Germany Background: It has been demonstrated that the lymphoid B cell follicle is an important HIV reservoir capable of harboring high levels of virus even when HIV is undetectable in the periphery. It is believed that the B cell follicle is an immune privileged site which blocks HIV-specific CTLs from entering, while allowing T follicular helper cells to pass freely in and out of the follicle. Here, we describe a population of HIV-specific cytolytic CD4+ T cells that have the ability to enter the B cell follicle and may be harnessed to reduce the follicular viral burden. Methods: We analyzed PBMCs from chronic HIV+ ART-naïve, HIV+ ART- treated and HIV- individuals, as well as lymphatic tissue from tonsils and lymph nodes of HIV+ and HIV- individuals. We used multicolor flow cytometry and immunofluorescence microscopy to determine the phenotype, frequency and functional properties of these cells. Furthermore, we assessed the plasticity of these cells in an in vitro culture and determined their ability to inhibit viral replication. Results: In the peripheral blood, we identified a CD4+ CXCR5+ T cells population expressing granzyme B and perforin that showed the ability to degranulate (CD107a) after stimulation. This cellular subset was significantly expanded in chronic HIV infection and contracted upon antigen reduction by ART. In response to Gag stimulation we found that a substantial portion of these cytolytic CD4+ T cells with follicular homing properties (TFC) were HIV-specific and further secreting interferon-γ. We next determined their frequency in

p ≤0.0074), IFN-gamma (0.0001≤ p ≤0.0007) and TNF-alpha (0.008≤ p ≤0.017) following incubation with IFN-alpha. Conclusion: In vitro treatment with IFN-alpha enhanced the suppressive capacity of ES NK cells and CD8+ T cells. Furthermore IFN-alpha treatments enhanced the production of cytokines by CP NK cells and CD8+ T cells in response to K562 cells and anti-CD3/28 antibodies respectively. Clinicians have a lot of experience using IFN-alpha. Treatment with this cytokine may therefore represent a way of potentiating NK cell and CD8+ T cell control of viral replication in HIV eradication studies. 284 FREQUENCIES AND DISTRIBUTION OF ENV-SPECIFIC B CELLS IN BLOOD VERSUS LYMPH NODES Alessandra Noto 1 , Andrew McDavid 2 , Phu Van 2 , Madeleine Suffiotti 1 , Agostino Riva 3 , Jean-Marc Corpataux 1 , Song Ding 4 , Craig Fenwick 1 , Raphael Gottardo 2 , Giuseppe Pantaleo 1 1 Lausanne University Hospital, Lausanne, Switzerland, 2 Fred Hutchinson Cancer Research Center, Seattle, WA, USA, 3 ASST Fatebenefratelli, Milan, Italy, 4 EuroVacc Foundation, Amsterdam, Netherlands Background: The large majority of the studies on B cells in HIV-1 infection have been performed in blood. Limited information is available on B cell populations from lymph nodes and on the association with the functional profile of T follicular helper (Tfh) cells. Methods: We have investigated the distribution and frequencies of Env- specific B cells in lymph nodes and blood of 14 HIV-1 infected viremic individuals and 11 aviremic ART treated individuals using flow and mass cytometry. Lymph node mononuclear cells (LNMC) were stained with Env probes together with a B cell panel of 32 isotope-conjugated antibodies. LNMCs were stimulated with PMA/ionomycin for 6h and stained with a panel of 32 markers defining the phenotype and function of Tfh cells. Results: The frequency of Env-specific B cells was increased in LNs as compared to blood (1.5% vs 0.5%, p<0.0001) and in LNs of viremics as compared to treated (1.73 fold). In blood, Env-specific B cells were contained within the resting memory and activate memory phenotype while the majority of LN Env-specific B cells were contained within the Germinal Center (GC) (55% in viremics and 20% in treated) and switched memory (35% in viremics and 75% in treated) B cells. The percentage of Env-specific B cells within the GC directly correlated with viral load and with the number of total GC B cells. LN Env-specific B cells from viremics expressed decreased levels of BCL-2, CXCR4 and CXCR5 and increased levels of CD95, KI67, BCL6, FCRL4, CXCR3 and T-bet. In viremics, we found a significant increase (2-3 fold) in the Tfh cells defined by the CXCR3+T- bet+ phenotype and IFN-γ production along with a significant decrease (2-3 fold) in Tfh cells expressing CCR4, CCR6 and producing IL-4. The CXCR3/T-bet/ IFN-γ signature of Tfh cells was strongly associated with the appearance of Env- specific B cells expressing CXCR3 and T-bet. In vitro experiments demonstrated IFN-γ as the causative factor inducing the differentiation of the CXCR3+T-bet+ memory B cells and as a strong suppressive factor of antibody production. Conclusion: The differences in composition of Env-specific B cells between blood and LN and the identification of Th1-like Tfh cells and IFN-γ as the main mechanisms affecting Env-specific B cell maturation will provide novel insights into strategies to develop optimal antibody responses in HIV infection and following vaccination. 285 T AND B CELL ALTERATIONS IN PERIPHERAL BLOOD AND LYMPH NODE IN ACUTE HIV INFECTION Supranee Buranapraditkun 1 , Hiroshi Takata 2 , Carlo Sacdalan 3 , Sopark Manasnayakorn 1 , Suthat Chottanapund 3 , Pattarawat Thantiworasit 1 , Peeriya Prueksakaew 3 , Khunthalee Benjapornpong 3 , Bessara Nuntapinit 4 , Timothy Schacker 5 , Merlin L. Robb 6 , Nelson L. Michael 7 , Jintanat Ananworanich 6 , Lydie Trautmann 2 1 Chulalongkorn University, Bangkok, Thailand, 2 HJF, Silver Spring, MD, USA, 3 SEARCH, Bangkok, Thailand, 4 Armed Forces Research Institute of Medical Sciences in Bangkok, Bangkok, Thailand, 5 University of Minnesota, Minneapolis, MN, USA, 6 HJF, Bethesda, MD, USA, 7 Walter Reed Army Institute of Research, Silver Spring, MD, USA Background: Both cellular and humoral immunity are important for the controlling HIV infection. However, little data is known about immune cells in different compartments in very early acute HIV infection (AHI). The RV254 Thai study captures participants in AHI from prior to viral load (VL) peak (Fiebig 1 and 2), at peak VL (Fiebig 3) and during VL decay (Fiebig 4/5).

Poster Abstracts

CROI 2018 100