Fig. 1
Macrophages trained with whole beta-glucan particles (WGP) inhibit tumor metastasis. Interstitial lung macrophages originating from the bone marrow can be trained with WGP in vivo and develop increased responsiveness to tumor cells or soluble tumor-derived factors. As a result, trained macrophages inhibit lung metastasis due to enhanced TNF-α production, increased phagocytosis and cytotoxicity to tumor cells and the modulation of T-cell responses. Innate immune training is mediated by enhanced synthesis of sphingolipids and the subsequent accumulation of S1P in macrophages, resulting in Drp1-regulated mitochondrial fission, which is required for increased mitochondrial ROS production and respiration, as well as increased cytotoxicity and TNF-α production
