**Abstract**

In this study, β-glucan was orally administered and irradiated with whole body 2 Gy. It was then confirmed that the mortality of mice and tumor growth of mice with tumors were significantly reduced. Since the number of leukocytes and lymphocytes increased with a single dose of β-glucan, the crystal was encountered where the radioprotective effect of β-glucan was probably increased by the hematopoietic action of irradiated mice. In previous studies, β-(1–3)-D-glucan extract has a radioprotective effect and an antitumor effect, and regarding the mechanism of action, the immune activity and antioxidant were elucidated. In this study, we investigated the antitumor effects of β-glucan on radiation, protection of immune disorders, and antioxidant effects. After intraperitoneal inoculation of about 2 x 106 sarcoma 180, ICR mice were administered 200 mg/kg β-glucan every other day every two weeks. We irradiated 2 Gy radiation 3 times and counted the number of white blood cells and lymphocytes. In addition, body weight and tumor size were measured 2 weeks after cancer cells were seeded. Antioxidant activity was measured using the AAPH (2,2-azobis (2-amidinopropane) dihydrochloride) method. There was a clear decrease in tumor size in the radiation and glucan groups compared to the group receiving only cancer cells that increased tumor size over time. Almost all mice inoculated with only cancer cells died two weeks after radiation, but two-thirds of radiation and the glucan group were alive. Regardless of radiation exposure, the number of leukocytes and lymphocytes increased when β-glucan was administered. Antioxidant activity has been demonstrated in both groups of glucans. These results may indicate that administration of β-glucan increases immune activity, prevents side effects during cancer radiotherapy, and provides a supplemental tool for the treatment of cancer.

**Keywords:** lymphocyte, CD4 + , CD8 + , β-(1–3)-D-glucan, radioprotection, radiotherapy
