(A) C57BL/6 WT mice (n=7, 8) were injected subcutaneously (s.c) with LLC or E0771 tumor cell lines. Once palpable tumors were formed (day 8), mice were orally administered with particulate β-glucan (800 µg, daily) or PBS with a gavage needle at indicated time. Tumor diameters were measured every three days and tumor volumes were then calculated. (B) On day 32 (LLC model) or day 35 (E0771 model), mice were killed and spleens were excised and weighed. Each point in the data plot represents the spleen weight of each mouse in grams. PBS-treated group was compared to particulate β-glucan treated group (WGP) in both models (C) Tumor tissues were excised and weighted from WGP or PBS-treated mice. (D) Flow cytometry analysis of the frequencies of M-MDSC (Ly6G−Ly6Chigh) and PMN-MDSC (Ly6G+Ly6Cint) in the spleens of LLC and E0771-bearing mice treated with PBS or particulate β-glucan (WGP). Cells were gated on CD11b+ cells. (E) Frequencies of M-MDSC and PMN-MDSC in the tumors of LLC and E0771-bearing mice treated with PBS or particulate β-glucan (WGP). Cells were gated on CD45+CD11b+ cells. *p<0.05, ** p<0.01, *** p<0.001.