635. In HIV Infected Patients Killing of Latently HIV-Infected CD4 T Cells by Autologous CD8 T Cells is Modulated by Nef.
Session: Poster Abstract Session: Pathogenesis and Immune Response
Thursday, October 4, 2018
Room: S Poster Hall
Posters
  • Poster_IDWeek 2018.pdf (998.0 kB)
  • Background:

    The PBMC of HIV-infected patients contain HIV-specific CD8 T cells and their potential targets, CD4 T cells latently infected by HIV. The role of HIV-specific CD8 T cells in the course of HIV infection and the way they affect the virus that resides in the latent reservoir, the resting memory CD4 T cells, is unknown. The association between HIV Nef protein and the cellular ASK1 protein protects the HIV-infected CD4 T cells from killing by CD8 T cells.

    Methods:

    CD8 and autologous CD4 T cells procured from PBMC of acute, chronic untreated, treated and AIDS patients were isolated by magnetic beads and co-incubated. Resting memory CD4 T cells (CD25-, CD69- and HLA-DR-) were isolated from activated CD4 T cells using a two-step bead depletion purification procedure. Formation of CD8-CD4 T-cell conjugates was observed by fluorescence microscopy and in situ PCR of HIV LTR DNA. Both conjugation and apoptosis were observed and quantified by imaging flow cytometry (ImageStream) using anti-human activated caspase 3 antibody and TUNEL assay. Formation of immunological synapse was observed by using anti-Perforin, anti γ-tubulin, and anti-LCK antibodies.

    Results:

    Following co-incubation we observed that CD8 T cells conjugate with and induce apoptosis of autologous CD4 T cells. In patients with acute infection or AIDS the conjugation activity and apoptosis were much higher compared to chronic HIV-infected patients. In patients on Anti-Retroviral Therapy (ART) low grade conjugation of CD4 T cells was observed by fluorescence microscopy (2.3±0.3 %), by in situ PCR of HIV DNA (3±0.6%) and by ImageStream analysis (2.5±0.5%). After co-incubation with autologous CD8 T cells 2.1±0.4 % of the CD4 T cells procured from patients on ART were undergoing apoptosis. Resting memory CD4 T cells were conjugated (1.9± 0.3%) and killed (2.2± 0.3%) by autologous CD8 T cells. Delivering a peptide that interferes with the Nef-ASK1 interaction, into the CD4 T cells, resulted in two-fold enhancement of their apoptosis by the autologous CD8 T cells (from 2.1±0.5% to 4.0±0.4%), with no effect on conjugation.

    Conclusion:

    CD8 T cells conjugate with and kill HIV-infected CD4 T cells throughout the course of HIV infection. We suggest that Nef inhibition may result in the elimination of the latent reservoir CD4 T cells by CD8 T cells.

    .

    Ziv Sevilya, PhD1, Udi Chorin, MD2, Orit Gal-Garber, PhD3, Einat Zelinger, PhD4, Dan Turner, MD5, Boaz Avidor, PhD5, Gideon Berke, PhD6 and David Hassin, MD7, (1)Assuta Ashdod Medical Center, Faculty of Health Sciences, Ben Gurion University of the Negev, Ashdod, Israel, (2)Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, (3)Interdepartmental Equipment Facility, Interdepartmental Equipment Facility, Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University, Rehovot, Rehovot, Israel, (4)Interdepartmental Equipment Facility, Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University, Rehovot, Rehovot, Israel, (5)Tel-Aviv Sourasky Medical Center Crusaid Kobler AIDS center and Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel, (6)Weizmann Institute of Science, Rehovot, Israel, (7)Internal Medicine a, Assuta Ashdod Medical Center, Faculty of Health Sciences, Ben Gurion University of the Negev, Ashdod, Israel

    Disclosures:

    Z. Sevilya, None

    U. Chorin, None

    O. Gal-Garber, None

    E. Zelinger, None

    D. Turner, None

    B. Avidor, None

    G. Berke, None

    D. Hassin, None

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