The anti-tumour effect of PAbM is dependent on CD8+ T cells and Gr-1+ CD11b+ monocytes and is mediated by Toll-like receptor 2 (TLR2). (a) The results shown are the growth curves of implanted mouse mammary carcinoma (MMC) tumours in C57BL/6 mice having received PBS (•), polysaccharide Agaricus blazei Murill (pAbM) (▪), pAbM with CD4 depletion (▽), pAbM with CD8 depletion (▾), or pAbM with Gr-1+ CD11b+ monocyte depletion (○). Data represent five mice in each treatment group. *P < 0·05, analysis of variance (anova). (b) The results shown are the growth curves of implanted TC-1 tumours in wild-type (WT) C57BL/6 mice receiving PBS (•), WT mice receiving PSK (▵), TLR2−/− mice receiving PBS (○), and TLR2−/− mice receiving PSK (▾). Data represent five mice in each treatment group. **P < 0·01, anova. (c) Concentration of interleukin-2 (IL-2), IL-12, interferon-γ, tumour necrosis factor-α (TNF-α), IL-10, and transforming growth factor-β (TGF-β) (mean ± SEM) Gr-1+ CD11b+ monocytes from WT or TLR2−/− mice on days 14 and 28 in PBS or pAbM-treated groups after tumour inoculation were assayed by ELISA. **P < 0·001 compared with pAbM treatment group in WT, *P < 0·05 compared with pAbM treatment group in TLR2−/−, anova. Similar results were observed in three independent experiments.