CD4 þ CD25 þ regulatory T cells (Treg) are potent immunosuppressive cells active in controlling normal pathological immune responses. The mechanisms of this suppression have been investigated under various conditions. In this report, tumor necrosis factor-related apoptosis inducing ligand (TRAIL)/death receptor 5 (DR5) was explored as one of the pivotal factors for the suppression and cytotoxicity induced by CD4 þ CD25 þ Treg. Cell death was involved in the suppression induced by activated CD4 þ CD25 þ Treg in vitro. The induction of CD4 þ T cell death was not mediated by the CD95/CD95L pathway, but rather depended upon the upregulation of TRAIL in the Treg. Blocking the TRAIL/DR5 pathway resulted in a significant reduction of the suppressive activity as well as the cytotoxic effects of Treg in vitro. Activated Treg displayed TRAIL-dependent cytotoxicity against CD4 þ T cells in vivo. The prolonged survival of allogeneic skin grafts induced by Treg was inhibited by DR5-blocking antibodies. Our findings suggest that the TRAIL/DR5 pathway is one of the mechanisms used by Treg to regulate immune responses both in vitro and in vivo.
The implosion dynamics of quasi-spherical wire arrays with different initial aspect ratios are investigated with a multi-element model, and the simulated results are compared with experimental results in the Qiangguang-1 Facility in 2011. According to the simulation, the pinch plasmas implode in different modes when the aspect ratios of the initial wire arrays are different. The aspect ratio of the wire array in shot 11259 is 0.76, and the simulated pinch plasma implodes onto the equatorial surface. In shot 11268, the aspect ratio is 1.33 and the plasma implodes onto the central axis. In shot 11270, the aspect ratio is 1.05 and the plasma implodes toward the central point of the load. The simulated shapes of the plasma shells are in good accordance with the experimental time-resolved x-ray framing images. The simulated imploding times are consistent with the experimental x-ray peak times. The quasi-spherical implosion is more effective in driving inertial controlled fusion.
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