Fig. 7: BG treatment and anti-PD1 therapy combine to inhibit liver metastasis.

a Representative images of livers from tumor-free mice (Normal Liver, NL, left) and mice treated with control (middle) and BG (right) at 14 days after iPo injection of PDAC-YFP cells. Tissues are stained using IHC to detect PD1 (brown) and nuclei (blue, hematoxylin). Scale bar, 200 μm (top) and 50 μm (bottom). b–d PD1⁺ cells detected by IHC in liver on Day 14 are shown as (b) cells per liver area, (c) cells per liver area in normal liver (n = 3) and after iPo injection of PDAC-YFP without treatment (n = 5) or after treatment with BG (n = 5), and (d) cells per metastatic lesion area (mm²). Kruskal-Wallis test with Dunn’s multiple comparisons testing (b, c) and unpaired two-tailed Welch’s t test (d). e Study design for (f). Data are representative of 2 independent experiments. f, Kaplan-Meier plot of mice following IS injection of PDAC-YFP cells in control (n = 15), BG-treated (n = 14), BG + anti-PD1 (n = 9) and anti-PD1 (n = 9) treated mice. Log-rank test. g–l Biopsies of metastatic lesions from patients with TNBC (n = 4) and melanoma (Mel, n = 5) were collected prior to (Pre-RX, left) and after 6 weeks of treatment (On-RX, right) with β-glucan (Odetiglucan) + anti-PD1 (pembrolizumab). g Representative IF images of paired liver biopsies stained for cytokeratin (CK, white), CD68 (green), PD-L1 (red), and nuclei (blue). Scale bars, 20 μm. h Quantification of tumor area pre- and on-treatment for individual patients. Scale bars, 20μm. i Representative IF images of paired liver biopsies stained for cytokeratin (white), CD80 (green), CD206 (pink), and nuclei (blue). Scale bars, 20 μm. j Quantification of myeloid infiltration/activation index for individual patients. k Representative IF images of paired liver biopsies stained for cytokeratin (white), CD8 (green), CD4 (red), and nuclei (blue). l Quantification of T cell infiltration/activation index for individual patients. m Conceptual model. β-glucan treatment activates Kupffer cells, which in turn recruit T cells to metastatic lesions resulting in decreased tumor cell proliferation and sensitization of metastatic lesions to anti-PD1 immunotherapy. Mean ± SD is shown (b, c, d). IHC, immunohistochemistry; IS, intrasplenic; IF, immunofluorescence; TNBC, triple-negative breast cancer.