کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2542437 | 1122702 | 2006 | 12 صفحه PDF | دانلود رایگان |
Down-regulation of cell-mediated immune functions occuring at late stages of cancer may be related to the thymic involution since thymus is the major site of T cell maturation, proliferation, and differentiation. We found that in Ehrlich's ascites carcinoma (EAC)-bearing mice there was profound depletion of CD4+ and CD8+ cells in peripheral blood with severely damaged thymus on 21st day of tumor inoculation. However, treatment with black tea at an antitumor dose of 2.5% significantly reduced such depletion and protected the thymus considerably from tumor onslaught. A search for the underlying mechanism revealed EAC-induced IL-7Rα down-regulation, inhibition of JAK3 and STAT5 phosphorylation, and decrease in Bcl-2/Bax ratio in thymocytes that finally led to thymocyte apoptosis in one hand and T cell maturation block on the other. Interestingly, black tea treatment prevented IL-7Rα down-regulation and protected the signaling cascade through JAK-STAT thereby inhibiting tumor-induced thymic apoptosis and ensuring proper functioning of this organ in tumor-bearing host.
Journal: International Immunopharmacology - Volume 6, Issue 3, March 2006, Pages 433–444