Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Bacterial Heat Shock Protein Groel (hsp64) Exerts Immunoregulatory Effects on T Cells by Utilizing Apoptosis
    (Public Library of Science, 2016) Nalbant, Ayten; Kant, Melis
    Aggregatibacter actinomycetemcomitans (Aa) expresses a 64-kDa GroEL protein belonging to the heat shock family of proteins. This protein has been shown to influence human host cells, but the apoptotic capacity of the GroEL protein regarding T cells is not yet known. The purpose of this study was to investigate the ability of A. actinomycetemcomitans GroEL (AaGroEL) protein to induce human peripheral blood T-cell apoptosis. Endogenous, purified AaGroEL protein was used as an antigen. In AaGroEL-treated T cells, the data indicated that phosphatidylserine exposure, an early apoptotic event, was dose- and time-dependent. The AaGroEL-treated T cells were also positive for active caspase-3 in a dose-dependent manner. The rate of AaGroEL-induced apoptosis was suppressed by the addition of the general caspase inhibitor Z-VAD-FMK. Furthermore, cleaved caspase-8 bands (40/36 kDa and 23 kDa) were identified in cells responding to AaGroEL. DNA fragmentation was also detected in the AaGroEL-treated T cells. Overall, we demonstrated that the endogenous GroEL from A. actinomycetemcomitans has the capacity to induce T-cell apoptosis. © 2016 Nalbant, Kant. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 16
    Aggregatibacter Actinomycetemcomitans Groel Protein Promotes Conversion of Human Cd4+ T Cells Into Ifn Gamma Il10 Producing Tbet+ Th1 Cells
    (Public Library of Science, 2012) Saygılı, Tahsin; Akıncılar, Semih Can; Akgül, Bünyamin; Nalbant Aldanmaz, Ayten
    One of the heat shock family protein (Hsp) expressing bacteria is the gram negative, periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa). A. actinomycetemcomitans' Hsp is a 64-kDa GroEL-protein, which has been shown to influence the host cells. In this study we used recombinant A. actinomycetemcomitans GroEL (rAaGroEL) protein as a model antigen to study GroEL-mediated T cell immune response. Human peripheral mononuclear cells (PBMCs), when stimulated with recombinant rAaGroEL, expressed early activation marker CD69 and IL-2R (CD25). CD25 and CD69 expressions were higher in CD4+ T cells compared to CD8+ T cells. rAaGroEL-responding CD4+ T cells expressed IL-10, IFNγ and TNFα cytokines. Interestingly, there were also IL-10 and IFNγ double cytokine producing CD4+ T cells. Additionally, IFNγ expressing CD4+ T cells were also T-bet positive. Altogether the results suggest that rAaGroEL protein affects CD4+ T cells to differentiate into IFNγ IL10-secreting T-bet+ Th1 cells.