Cytotoxic T lymphocyte perforin and Fas ligand working in concert even when Fas ligand lytic action is still not detectable

Hassin, David; Garber, Orit Gal; Meiraz, Avihai; Schiffenbauer, Yael S.; Berke, Gideon

doi:10.1111/j.1365-2567.2011.03426.x

Cited by 86 publications

(84 citation statements)

References 40 publications

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“…However, we noted in subsequent in vivo studies that while FasL-deficient CD8 + T cells exhibited impaired cytotoxicity of alloprimed IgG1 + B cells, as compared to wild-type CD8 + T cells, perforin-deficient CD8 + T cells exhibited moderate levels of cytotoxicity. Our results are consistent with a recent report indicating that perforin-mediated CD8 + T cell cytotoxicity is inhibited in the absence of FasL, suggesting that perforin-mediated cytotoxicity requires the presence of FasL for efficient killing (38). Alternatively, CD8 + T cells may utilize perforin to downregulate antibody production in other ways, in addition to killing B cells.…”

Section: Discussionsupporting

confidence: 93%

Alloprimed CD8+ T Cells Regulate Alloantibody and Eliminate Alloprimed B Cells Through Perforin- and FasL-Dependent Mechanisms

Zimmerer

Pham

Wright

et al. 2014

American Journal of Transplantation

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While it is well known that CD4+ T cells and B cells collaborate for antibody production, our group previously reported that CD8+ T cells downregulate alloantibody responses following transplantation. However, the exact mechanism involved in CD8+ T cell-mediated downregulation of alloantibody remains unclear. We also reported that alloantibody production is enhanced when either perforin or FasL is deficient in transplant recipients. Here, we report that CD8+ T cell-deficient transplant recipient mice (high alloantibody producers) exhibit an increased number of primed B cells compared to wild-type transplant recipients. Furthermore, CD8+ T cells require FasL, perforin, and allospecificity to downregulate posttransplant alloantibody production. In vivo CD8-mediated clearance of alloprimed B cells was also FasL- and perforin-dependent. In vitro data demonstrated that recipient CD8+ T cells directly induce apoptosis of alloprimed IgG1+ B cells in co-culture in an allospecific and MHC class I-dependent fashion. Altogether these data are consistent with the interpretation that CD8+ T cells downregulate posttransplant alloantibody production by FasL- and perforin-dependent direct elimination of alloprimed IgG1+ B cells.

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Section: Discussionsupporting

confidence: 93%

Alloprimed CD8+ T Cells Regulate Alloantibody and Eliminate Alloprimed B Cells Through Perforin- and FasL-Dependent Mechanisms

Zimmerer

Pham

Wright

et al. 2014

American Journal of Transplantation

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“…CD8 T cells can suppress viral spread by the production of interferon‐ γ , by the induction of apoptosis via the cell surface receptors Fas–Fas ligand, and by secreted perforin and granzymes. Several studies have also demonstrated that expression of perforin can serve as a marker of ongoing activation and killing capacity of CD8 T cells . Apart from their positive effects of controlling viral spread, CTL have been shown to cause tissue damage in viral infections, such as in viral myocarditis and viral hepatitis .…”

Section: Introductionmentioning

confidence: 99%

Peripheral blood mononuclear cells of HIV‐infected patients contain CD8 T cells that form conjugates with and kill HIV‐infected autologous CD4 T cells

et al. 2015

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Summary Peripheral blood mononuclear cells (PBMC) of untreated, HIV‐infected patients contain HIV‐specific CD8 T cells as well as their corresponding targets, HIV‐infected CD4 T cells. To determine if CD4 T‐cell depletion in HIV‐infected patients may result from autologous CD8–CD4 T‐cell interaction, CD8 and CD4 T cells procured from PBMC of acute and chronic untreated HIV‐infected patients were sorted and co‐incubated. Formation of CD8‐CD4 T‐cell conjugates was observed by fluorescence microscopy. Apoptosis of CD4 T cells in conjugation was recorded by digitized images and was further observed and measured by FACS using Annexin staining. Perforin expression in the CD8 T cells was measured using intracellular monoclonal perforin antibody staining. HIV DNA in the conjugated CD4 T cells was detected by in situ PCR. We found that 6·1 ± 0·5% of CD4 T cells from acute HIV‐infected patients and 3·0 ± 0·5% from chronic HIV‐infected patients formed CD8–CD4 T‐cell conjugates. Annexin binding and cell morphology typical of apoptosis were observed in the conjugated CD4 T cells. The majority of CD8 T cells that had conjugated to CD4 T cells expressed perforin. The conjugated CD4 T cells exhibited nuclear HIV DNA. CD8 T cells and HIV‐infected CD4 T cells, both procured from the PBMC of untreated HIV‐infected patients, form conjugates. Apoptotic lytic activity has been observed in the conjugated CD4 T cells. We propose that CD4 T‐cell annihilation in HIV‐infected patients results, at least in part, from the interactions of perforin‐rich CD8 T cells with autologous, HIV‐infected CD4 T cells.

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“…Although perforin mediated granzyme B delivery is described as an early event and Fas/FasL induced death is described as occurring late, the only available technologies available to evaluate this activity in real time require sophisticated microchip technology. (17) Additionally, monitoring of cytotoxicity by fluorescence based approaches leads to a relatively low signal to noise ratio, due to background fluorescence from live or fixed cells. We reasoned that a protease-inducible, luminescent biosensor introduced into target cells alone would allow us to measure CTL-induced caspase induction in a living cell continuously, in a convenient, non-radioactive, microplate format with minimal background signal.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Detection of CTL Function Reveals Distinct Patterns of Caspase Activation Mediated by Fas versus Granzyme B

Figueira

Vrazo

et al. 2014

The Journal of Immunology

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Activation of caspase-mediated apoptosis is reported to be a hallmark of both granzyme B- and Fas- mediated pathways of killing by cytotoxic T lymphocytes (CTL); however, the kinetics of caspase activation remain undefined due to an inability to monitor target cell-specific apoptosis in real time. We have overcome this limitation by developing a novel biosensor assay that detects continuous, protease specific activity in target cells. Biosensors were engineered from a circularly-permuted luciferase, linked internally by either caspase 3/7 or granzyme B/caspase 8 cleavage sites, thus allowing activation upon proteolytic cleavage by the respective proteases. Co-incubation of murine CTL with target cells expressing either type of biosensor led to a robust luminescent signal within minutes of cell contact. The signal was modulated by the strength of TCR signaling, the ratio of CTL/target cells, and the type of biosensor utilized. Additionally, the luciferase signal at 30 minutes correlated with target cell death, as measured by 51Cr release assay. The rate of caspase 3/7 biosensor activation was unexpectedly rapid following granzyme B compared to Fas-mediated signal induction in murine CTL; the latter appeared gradually after a 90 minute delay in perforin or granzyme B deficient CTL. Remarkably, the Fas dependent, caspase 3/7 biosensor signal induced by perforin-deficient human CTL was also detectable after a 90 minute delay when measured by re-directed killing. Thus we have utilized a novel, real-time assay to demonstrate the distinct pattern of caspase activation induced by granzyme B versus Fas in human and murine CTL.

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Cytotoxic T lymphocyte perforin and Fas ligand working in concert even when Fas ligand lytic action is still not detectable

Cited by 86 publications

References 40 publications

Alloprimed CD8+ T Cells Regulate Alloantibody and Eliminate Alloprimed B Cells Through Perforin- and FasL-Dependent Mechanisms

Alloprimed CD8+ T Cells Regulate Alloantibody and Eliminate Alloprimed B Cells Through Perforin- and FasL-Dependent Mechanisms

Peripheral blood mononuclear cells of HIV‐infected patients contain CD8 T cells that form conjugates with and kill HIV‐infected autologous CD4 T cells

Real-Time Detection of CTL Function Reveals Distinct Patterns of Caspase Activation Mediated by Fas versus Granzyme B

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