Alcohol abuse has been commonly associated with enhanced susceptibility to pathogens. Studies on the effects of ethanol on the immune system are complicated by a lack of consensus on whether ethanol activates, inhibits or has no effect on immune cells. We present data showing that acute exposure of T cells to ethanol elicits responses that broadly parallel responses seen in normally stimulated T cells such as the formation of the immune synapse, polarization of the microtubule organizing center (MTOC) to the synapse and tyrosine phosphorylation of signaling proteins as seen when the T cell Receptor (TcR) engages antigen-MHC. However, incomplete activation of the T cell signaling program leads to unresponsive or anergic T cells. Our data suggests the hypothesis that ethanol can activate T cells in a manner that leads to anergy. We have found that ethanol triggers calcium signaling and this has provided one of the primary tools for analyzing the effects of ethanol on T cells. Ethanol induced calcium transients are dose-dependent and are comparable to those triggered by low doses of anti-TcR antibody. This is important because it allows us to compare ethanol dependent signaling to that normally triggered through stimulation of the T cell receptors. Analysis of the calcium signaling pathway indicates that ethanol-stimulated calcium transients depend on calcium entry and are likely due to opening of CRAC type calcium channels. The observed calcium transients go a long way towards explaining how ethanol may stimulate T cells and provides a mechanism for immune suppression through the observed translocation of NF-AT in ethanol pulsed cells. The translocation of NF-AT is particularly important because of reports that it plays a crucial role in triggering anergy and immunosuppression. Taken together, these data can help explain how ethanol can both activate T cells and cause immunosuppression.
| Identifer | oai:union.ndltd.org:UTEXAS/oai:repositories.lib.utexas.edu:2152/3644 |
| Date | 29 August 2008 |
| Creators | Naqvi, Hassan Raza, 1976- |
| Contributors | Poenie, Martin F. |
| Source Sets | University of Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | electronic |
| Rights | Copyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works. |
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