THE BIOLOGY OF MACROPHAGES

The main properties of the mononuclear phagocytic system (MPS) are sum marized, focusing on their relevance within the framework of the stead y-state and the inducible functions of the mammalian immune system, mo re specifically the immune system of the laboratory mouse, a reference vertebrate which remains the best studied. A peculiar attention is gi ven to the rationale underlying the generation of so-called specific t ools and reagents whose use is promoted to characterize this lineage, whatever the level under study, i.e. tissular, cellular, or subcellula r levels. As one lineage among other lineages of the hemopoietic syste m, the MPS is characterizable by constitutive and inducible phenotypic and functional markers whose combination is unique for a given tissul ar micro-environment. Considering our present understanding of the inn ate and adaptive immune system functions, some of the properties of th e MPS are discussed in relation with properties of another recently re cognized hemopoietic lineage, namely the dendritic leukocyte system.