Distribution of regulatory T cells in tumor progressing

• Main Authors: Tzu Chuan Ho, 何慈娟
• Other Authors: C. R. Shen
• Format: Others
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/84858203177777877560

碩士 === 長庚大學 === 醫學生物技術暨檢驗學系 === 98 === Elicitation of Tregs in cancer patients has been shown to contribute to the progression of tumor. However, it remains unclear whether the increased Requlatory T cells (Treg) are indeed associated with the fluctuation of other immune cells and/or mediators during the tumor development. This study aimed to address such issues in a mouse tumor model by subcutaneously grafting CT-26-Luc, a murine colon cancer cell line stably express luciferase, in BALB/c mice. A non-invasive in vivo imaging system (IVIS) was adapted to monitor the tumor growth. Different populations of CD4+, CD8+ and Treg cells as well as cytokine secreting T cells in peripheral blood, spleen, and tumor draining lymph nodes were analyzed by multi-color flow cytometery. The release of cytokines including TGF-β, IL-10, IL-17 and IFN-γby mononuclear cells prepared from Haose tissues or organe , within in response to PMA or CT26 cells in vitro were quantified by ELISA. The results show that the frequency of CD4+ T cells was reduced while that of CD8+ T cells was increased in tumor draining lymph nodes in tumor-bearing mice, although such a phenomenon did not appear the same in peripheral blood and spleens. Moreover, NK and NKT cells were found to be slightly enhanced following the declination of CD4+ T cells in spleens of the tumor-bearing mice. Additionally, in the early stage of tumor development, mice harbored more IFN-γ secreting CD4+ and CD8+ cells; in contrast, the increasing numbers of IL-10 secreting CD4+ cells were found in the later stage of tumor-bearing mice . In addition, the numbers of Treg cells, CD4+CD25+ or CD4+CD25+Foxp3+ appeared to relatively increase in peripheral blood and spleens of the tumor bearing mice. Finally, IL-17 secreting CD4+ T cells (Th17), were also found to be significantly increased in later stage of tumor development, although both IL-17 secreting CD4+ and CD8+ T cells were both enhanced in these tumor bearing mice. These results indicate the changes of actioation and suppression of immune responses seem to fluctuate by examiny levels of a number of soluble mediators and numbers of different immune cells in different stages of tumor development. Additional studies are necessary to address specific questions.