Macrophage Marker Recombinant Mouse mAb (S-5675)

Macrophages are long-lived phagocytic cells widely distributed throughout the body's tissues, derived from bone marrow hematopoietic stem cells or embryonic precursors; they constitute the first line of innate immunity and bridge innate and adaptive immunity. Their core function is phagocytosis: they recognize and internalize pathogens or apoptotic cells through complement receptors, Fcγ receptors, and scavenger receptors, achieve killing and degradation within phagolysosomes via the acidic environment and reactive oxygen species, and then present processed antigens to T cells via MHC class II molecules to initiate specific immune responses. Macrophages exhibit marked tissue heterogeneity and functional plasticity: macrophages resident in different organs acquire specific names and phenotypes, such as Kupffer cells in the liver, microglia in the brain, alveolar macrophages in the lung, and osteoclasts in bone; driven by microenvironmental signals, they can polarize into a pro-inflammatory (M1-like) state, induced by IFN-γ/LPS and characterized by high secretion of TNF, IL-12, and reactive oxygen species, or an anti-inflammatory/reparative (M2-like) state, induced by IL-4/IL-13 and involved in tissue repair and resolution of inflammation. In the tumor microenvironment, macrophages are often educated into M2-like tumor-associated macrophages that promote tumor progression by fostering angiogenesis, immune suppression, and metastasis, making them an important target in current cell therapy and drug delivery research.