Anti-TBX21 monoclonal antibody, clone FQS0412

In order to analyze the effect of vitamin E on Th1 and Th2 cytokine production, porcine peripheral blood mononuclear cells (PBMC) were isolated from healthy pigs (n = 8) and cultured with either 0, 10, 50, or 100 mu M of vitamin E (alpha-tocopherol). PBMC were stimulated with PHA for either, 24 h to determine: (a) the concentration of tocopherol incorporated into the cell membrane, (b) cytokine production and (c) Th1 and Th2 regulators gene expression; or 72 h to determine the proliferation of PBMC. Vitamin E was incorporated into the PBMC in a dose dependent manner, giving as a result a high proliferation of cells irrespective of the dose of vitamin E used. Regarding cytokine production, vitamin E consistently decreases the mRNA expression and the percentage of cells producing IL-10. Vitamin E did not influence the production of IFN-gamma but the lowest level of vitamin E (10 mu M) was sufficient to maximally increase the proportion of cells producing IL-2, to diminish IL-4, and discreetly increase the mRNA expression of TBX21 vs. GATA3. In conclusion, our results revealed that vitamin E is able to suppress IL-10 production and to influence the production of IL-2, IL-4, and maybe TBX21. Vitamin E clearly has immunomodulatory effects, though further work in vivo to determine the physiological nature of these effects is warranted. (c) 2009 Elsevier B.V. All rights reserved.

Acquired aplastic anemia (AA) is a potentially fatal bone marrow (BM) failure syndrome. IFN-gamma-producing Th1 CD4(+) T cells mediate the immune destruction of hematopoietic cells, and they are central to the pathogenesis. However, the molecular events that control the development of BM-destructive Th1 cells remain largely unknown. Ezh2 is a chromatin-modifying enzyme that regulates multiple cellular processes primarily by silencing gene expression. We recently reported that Ezh2 is crucial for inflammatory T cell responses after allogeneic BM transplantation. To elucidate whether Ezh2 mediates pathogenic Th1 responses in AA and the mechanism of Ezh2 action in regulating Th1 cells, we studied the effects of Ezh2 inhibition in CD4(+) T cells using a mouse model of human AA. Conditionally deleting Ezh2 in mature T cells dramatically reduced the production of BM-destructive Th1 cells in vivo, decreased BM-infiltrating Th1 cells, and rescued mice from BM failure. Ezh2 inhibition resulted in significant decrease in the expression of Tbx21 and Stat4, which encode transcription factors T-bet and STAT4, respectively. Introduction of T-bet but not STAT4 into Ezh2-deficient T cells fully rescued their differentiation into Th1 cells mediating AA. Ezh2 bound to the Tbx21 promoter in Th1 cells and directly activated Tbx21 transcription. Unexpectedly, Ezh2 was also required to prevent proteasome-mediated degradation of T-bet protein in Th1 cells. Our results demonstrate that Ezh2 promotes the generation of BM-destructive Th1 cells through a mechanism of transcriptional and posttranscriptional regulation of T-bet. These results also highlight the therapeutic potential of Ezh2 inhibition in reducing AA and other autoimmune diseases.