Effect of thymosin alpha-1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro

Thymosin alpha 1 (T alpha 1) has been shown to have beneficial effects on numerous immune system parameters, but little is known about the effects of T alpha 1 on patients with gastric carcinoma. The objective of this study was to determine the effect of T alpha 1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro, and to evaluate its efficacy as an immunoregulatory factor in patients with gastric carcinoma. We compared the effect of T alpha 1 on the frequency of CD4(+) and CD8(+) T cells, especially the CD4(+)CD25(+)Foxp3(+) Tregs in peripheral blood mononuclear cells (PBMCs) from gastric carcinoma patients (N = 35) and healthy donors (N = 22). We also analyzed the changes in the proliferation of PBMCs in response to treatment with T alpha 1, and examined the production of Th1, Th2, and Th17 cytokines by PBMCs and tumor-infiltrating lymphocytes. The treatment of PBMCs from gastric cancer patients, with T alpha 1 (50 mu g/mL) alone increased the percentage of CD4+CD25+Foxp3+ (suppressive antitumor-specific Tregs) from 1.68 +/- 0.697 to 2.19 +/- 0.795% (P < 0.05). Our results indicate that T alpha 1 increases the percentage of Tregs and IL-1 beta, TNF-alpha, and IL-6 in vitro.