Unique molecular characteristics of the environmental responses of mucosal macrophages

Macrophages are thought to be the cells that initially respond to environmental information and transmit this information to other immune cells. We hypothesize that there is a "network system" consisting of various tissue macrophages; the macrophages respond to stimulation and transmit secondary information to neighboring cells, which is important for the maintenance of homeostasis. Macrophages exist in all animal organs as tissue macrophages, and their cellular characteristics may change as an adaption to tissue-specific environments. It is believed that mucosal macrophages are particularly important in the macrophage network system because mucosa exist where there is regular exposure to foreign substances. However, the molecular mechanism by which intestinal mucosal macrophages respond to the external environment is not yet clear. In this review the biological characteristics of mucosal macrophages are introduced and how they recognize and eradicate various foreign substances is discussed.