Cooperative role of T lymphocytes and macrophages in anti-tumor activity of mice pretreated with schizophyllan (SPG).

Anti-tumor activity was studied in mice injected with Schizophyllan (SPG), a glucan produced by Schizophyllum commune Fries. SPG-injected mice rejected subcutaneously inoculated sarcoma-180 and the anti-tumor activity was shown to be mediated by host spleen and lymph node cells. The anti-tumor activity lasted as long as 60 days after the SPG administration as assessed by transfer of cells into normal recipients. Cells involved in anti-tumor activity were shown to be T lymphocytes since anti-tumor activity was diminished when lymph node cells from SPG-treated mice were treated with anti-Thy-1.2 sera plus complement, whereas cells passed through a nylon wool column retained the activity. Macrophages were also shown to be involved since administration of carrageenan or trypan blue into the host decreased the inhibition ratio of tumor growth. It was concluded that anti-tumor activity in SPG-treated mice was mediated by the cooperation of T lymphocytes and macrophages, thus the impairment of either function decreased anti-tumor activity.