The Mononuclear Phagocyte System (MPS) is a network of immune cells that play a crucial role in the body's defense against pathogens. It primarily consists of monocytes, macrophages, and dendritic cells, which originate from bone marrow and migrate to various tissues. These cells are responsible for engulfing and digesting foreign substances, dead cells, and debris, thus maintaining tissue homeostasis. The MPS is essential for both innate and adaptive immunity. Macrophages can present antigens to T cells, helping to initiate a more specific immune response. Additionally, the MPS contributes to inflammation and tissue repair, highlighting its importance in overall health and disease management.