The Changes of Lymphocytes and Immune Molecules in Irradiated Mice by Different Doses of Radiation

Abstract The effects of different radiation doses on T and B lymphocyte functional subsets and the changes of immune cells and immune molecules were observed in mice at different times post-irradiation to provide a theoretical basis for the changes of immune cells affected by radiation. In this study, the changes of T and B immune cells and immune-related molecules were observed at 1, 3, 7, 14, and 21 d after single irradiation of 2 Gy, 4 Gy, and 6 Gy. The results showed that white blood cells (WBC), lymphocytes (LYMPH), and lymphocyte percentage (LYMPH%) in peripheral blood of mice were significantly reduced and reached the lowest point 3 d after irradiation. Flow cytometry results showed that the percentages of CD3 + T and CD8 + /CD3 + T lymphocytes in spleen and thymus were significantly decreased, and the percentages of CD19 + B lymphocytes in spleen and CD4 + /CD3 + T lymphocytes in thymus were also decreased. However, the percentages of splenic NK cells, CD4 + /CD3 + T cells, and CD4 + /CD8 + ratios in spleen and thymus were increased. Most of the indicators fell to the lowest or highest point 3 d after irradiation, indicating that immune function was suppressed at this time. From 7 to 21 d after irradiation, most immune cells gradually recovered. Single irradiation of 2 Gy, 4 Gy, and 6 Gy increased the contents of IL-1β, IL-2, IL-6, IL-17, TNF-α, TGF-β, and IFN-γ in serum of mice and decreased the contents of anti-inflammatory factors IL-4 and IL-10. The serum levels of immunoglobulin IgA, IgG, IgM and complement C3, C4 were significantly increased after irradiation. Our study showed that a single dose of 2 Gy, 4 Gy, and 6 Gy induced immunosuppression in mice, and maximum immunosuppression was achieved 3 d after irradiation. At this time, CD19 + B lymphocytes were the most sensitive, followed by CD3 + T lymphocytes, and NK cells were the most resistant. The radiosensitivity of CD8 + /CD3 + T lymphocytes was slightly higher than that of CD4 + /CD3 + T lymphocytes.