T-bet(+)GATA-3(+)Th1/2杂合细胞在放射性肺损伤中的作用及机制研究

放射性肺损伤是肺癌放疗的常见并发症，目前该病的损伤机制仍未明确。既往我们发现放射性肺损伤中存在Th1/Th2免疫失衡，进一步研究发现在放射性肺损伤的两期，即早期放射性肺炎期（Th1型反应）和晚期肺纤维化期（Th2型反应）均存在一种T-bet(+)GATA-3(+)Th1/2杂合细胞。为探讨该杂合细胞在放射性肺损伤中的免疫调节功能，本项目拟通过构建荷瘤及无瘤小鼠放射性肺损伤模型，采用流式细胞术探讨放射性肺损伤中Th1、Th2和T-bet(+)GATA-3(+)Th1/2杂合细胞间的动态变化关系；通过免疫荧光, smFISH, 流式细胞学检测明确T-bet(+)GATA-3(+)Th1/2杂合细胞在放射性肺损伤中的调节机制；通过体外诱导T-bet(+)GATA-3(+)Th1/2杂合细胞干预探讨该杂合细胞对放射性肺损伤的调控作用。旨在探索放射性肺损伤中的免疫调控机制和新的免疫治疗途径。

Radiation-induced lung injury (RILI) is a major complication of thoracic radiotherapy. It be regarded as a continuous progression of events, which contains two discernable phase named radiation pneumonia and radiation pulmonary fibrosis. At present, the mechanisms involved in RILI remain incompletely understood. In the previous research, we found that the immune imbalance of Th1/Th2 exist in the progress of RILI. Further study showed that a type of cell called Th1/2 hybrid cells which co-expresses T-bet and GATA-3 that express obviously in both radiation pneumonia period(Th1 reaction period) and radiation pulmonary fibrosis period(Th2 reaction period). Since the Th1/2 hybrid cells can simultaneously secrete both IFN-γ and IL-4 to regulate the immune balance, we propose that there is a regulatory mechanism in the RILI that on the quantitative modulation of Th1/2 hybrid cells to the prevention of excessive Th1 or Th2 response. In this study, we first will use C57BL/6 mice to establish models of tumor-bearing and tumor-free RILI. By using flow cytometry analysis, we will to confirm the dynamic relationship between Th1,Th2 and T-bet(+)GATA-3(+)Th1/2 hybrid cells in these mice’s lung and blood before and after radiation. Then we will use immunofluorescence, smFISH and flow cytometry analysis to explore the regulatory mechanism of T-bet(+)GATA-3(+)Th1/2 hybrid cells in radiation-induced lung injury. T-bet(+)GATA-3(+)Th1/2 hybrid cells will be culturing in vitro and injecting into mice to clarify the regulating effect of T-bet(+)GATA-3(+)Th1/2 hybrid cells on immune imbalance of Th1/Th2 in RILI. This study aims at exploring the new immunoregulation mechanism of radiation-induced lung injury and probably immunotherapy method.