452. Perforin rich CD8+ T cells form conjugates and kill autologous CD4+ T Cells in peripheral blood of HIV-infected patients, accounting for their decline
Session: Poster Abstract Session: HIV Pathogenesis and Immunity
Friday, October 21, 2011
Room: Poster Hall B1
  • Poster.pdf (399.5 kB)
  • Background: During HIV infection, a decline in CD4 cells occurs via an unknown mechanism. PBMC of HIV-infected patients contain HIV-specific CD8 cells and their targets, CD4 cells latently infected by HIV. Here, for the first time, the interaction of CD8 cells and CD4 cells, both procured from PBMC of untreated HIV-1infected patients was explored. We hypothesize that CD4 cell decline is mediated by conjugation with HIV-specific CD8 cells loaded with Perforin, a marker of ongoing activation and killing capacity. 

    Methods: CD8 and CD4 cells from PBMC of 11 acute and 11 latent untreated HIV-infected patients were sorted using magnetic beads, followed by conjoined incubation. CD8-CD4 cell conjugates were counted by fluorescent microscopy. Killing activity of CD8 cells against CD4 cells was measured by the Annexin V Fitc Apoptosis Detection Kit. Perforin expression of CD8 cells was measured by FACS and in the conjugates by fluorescent microscopy.

    Results: 6.1% ±0.5 of the CD4 cells from acute and 3.0% ±0.5 from latent HIV-infected patients, formed CD8-CD4 cells conjugates compared to 0.9% ±0.06 in HIV-negative controls, p(F) <0.0001. Apoptotic lytic activity was measured  in 18.6% ±2.4 of the cells from acute patients compared to 10.9% ±2.0 from latent patients and 8.8 % ±1.0  from controls  p(F)= 0.0008. Annexin binding and apoptotic morphology were observed in CD4 cells conjugated to CD8 cells during acute and latent phases of HIV infection. Using FACS, 41% ±4.4 of CD8 cells expressed Perforin in the acute phase and 27% ±3.6 in the latent phase, compared to 12% ±2.8  in controls p (F)<0.0001. Fluorescent microscopy revealed that 60% of conjugated CD8 cells were Perforin-positive in the acute and latent phases of infected patients.

    Conclusion: CD8 cells and CD4 cells procured from untreated HIV-infected patients during the acute and latent phases form conjugates. Apoptotic lytic activity is observed in conjugated CD4 cells during the acute phase of infection and with disease progression, CD8 cells decrease their cytotoxic activity, retaining conjugate formation with high Perforin content. Based on these results, we propose that in HIV-infected patients CD4 cell obliteration results from an ongoing activated Perforin-rich CD8 cell interaction with CD4 cells. 

    Subject Category: H. HIV/AIDS and other retroviruses

    Udi Chorin1, Orit Gal-Garber2, Dan Turner1, Boaz Avidor1, Gideon Berke3 and David Hassin1, (1)Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, (2)Weizmann Institute of Science, Rehovot, Israel, (3)Weizmann Institute of Science, Rehovot, Israel


    U. Chorin, None

    O. Gal-Garber, None

    D. Turner, None

    B. Avidor, None

    G. Berke, None

    D. Hassin, None

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