Title: Low-dose radiation stimulates CD4 T-cell activation through enhancing MHC-II expression

Authors: Jinbo Li, Ruilei Teng, Qian Wang, Jianliang Jin, Xianhui Lv, Dengshun Miao

Institution: The Research Center for Bone and Stem Cells, Department of Anatomy, Histology and Embryology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.

Abstract: Acute immune response is inducible in ionizing radiation therapy and the pathological formation of secondary diseases is reportedly promoted by such immune response. CD4 T cells have been proved to involve in the de­velopment of many kinds of diseases; however, its role in radiation-induced immune response is unknown. In this study, C57BL6 mice were divided into four groups and irradiated with X-ray at doses of 0, 2, 4 and 8Gy, respec­tively. One week post radiation, activation of CD4 T cells, MHC-II expression and proliferation of macrophages, as well as percentages of subsets of lymphocytes were analyzed by immunohistochemistry and flow cytometer. The results showed that the percentage of activated CD4 T cells increased in the spleen and lymph nodes in mice irradiated at low-doses. Enhanced antigen presentation mediated by MHC-II was intensively related to increased CD4 T-cell activation. Increased proliferation and MHC-II expression of macrophages induced by low-dose ra­diation (LDR) contributed to CD4 T-cell activation. Increased activation of CD4 T cells correlated with their ca­pacity of radioresistance. These results indicate that CD4 T-cell activation caused by low-dose radiation is closely related to enhanced MHC-II expression of macrophages and contributes to its radioresistance.

Keywords: immunology, radiation, T-cell activation, MHC-II

Full Text: PDFJBR-2013-0027.pdf

J Biomed Res published on July 12th, 2013, doi: 10.7555/JBR. 27. 20130027