Production of cytokines by peritoneal macrophages and splenocytes after exposures of mice to low doses of X-rays

摘要

We have shown previously that irradiations of mice with 0.1 or 0.2 Gy of X-rays stimulate anti-tumour cytotoxic activities of peritoneal macrophages and spleno-cytes enriched for NK lymphocytes and suppress the development of pulmonary tumour colonies.The up-regulated cytotoxicities were related to the production of nitric oxide by macrophages,and perforin and Fas ligand by the spleno-cytes,but specific blockade of these pathways did not totally suppress the effector cell-mediated cytolysis of the tumour target.Hence,other factors such as cytotoxic/cytostatic cytokines might have been produced by the effector cells.To test this possibility peritoneal macrophages and splenocytes were isolated from BALB/c mice which had been either once or tentimes whole body-irradiated with the total doses of 0.1 and 0.2 Gy of X-rays and assayed for the levels of IL-1beta,IL-2,IL-12,IFN-gamma and TNF-alpha in the incubation medium using the respective ELISA kits.The results demonstrate that both single and multiple exposures to the two low doses of X-rays significantly stimulate secretion of IL-1beta,TNF-alpha and IL-12 by macrophages and IL-2 and IFN-gamma by splenocytes,but the kinetics and magnitude of the induced changes in the production of these cytokines differ between the two irradiation protocols.