Beta-(1-3),(1-6)-D-glucan Enhances the Effect of Low-dose Cyclophosphamide Treatment on A20 Lymphoma in Mice

Abstract

Background: Beta-(1-3),(1-6)-D-glucans demonstrate antitumor effects in vivo due to the activation of innate immune cells. Cyclophosphamide (CY) enhances natural or therapeutically induced antitumor immune responses by reducing the number and activity of regulatory T (Treg) cells. Materials and Methods: We tested whether oral administration of soluble beta-glucan augmented the inhibitory effect of intraperitoneally injected low-dose CY (30 mg/kg) on subcutaneously growing A20-lymphoma in Balb/c-mice. Results: Administration of CY one week after tumor inoculation significantly diminished tumor growth (p=0.009) and the absolute number of Treg cells in the peripheral blood compared with phosphate buffered saline-treated mice (p=0.036). Treatment of CY pre-conditioned lymphoma-bearing mice with daily beta-glucan (400 μg/mouse) between day 9 and day 13 after tumor injection significantly delayed onset of tumor growth, compared to mice which received only CY (p=0.01). Conclusion: Beta-(1-3),(1-6)-D-glucan could be useful in the treatment of lymphoma after low-dose chemotherapy with CY.