Plasma membrane receptors of the mononuclear phagocyte system

Abstract

Plasma membrane receptors control macrophage activities such as growth, differentiation and activation, migration, recognition, endocytosis and secretion. They are therefore important in a wide range of physiological and pathological processes including host defence, inflammation and repair, involving all systems of the body including the arterial wall and nervous system. The versatile responsiveness of these cells to various stimuli depends on their ability to express a large repertoire of receptors, some restricted to macrophages and closely related cells, others common to many cell types. This volume contains reviews of the macrophage receptors that are best characterized and deals with aspects of signal transduction and function of the actin cytoskeleton. Our introduction is designed to place these topics in perspective. We summarize features of constitutive and induced mononuclear phagocyte distribution within the body and consider receptor expression and macrophage responses in the context of cell heterogeneity associated with its complex life history. We classify receptors discussed in detail in other chapters, list ligand-binding properties that are not as well defined, and briefly review general features of receptor function in macrophages. An understanding of macrophage receptor biology should bring insights into the contribution of these cells to physiology and disease and result in an improved ability to manipulate activities within the mononuclear phagocyte system.

Macrophages in Drosophila embryos and L2 cells exhibit scavenger receptor-mediated endocytosis.

“…Macrophages play multifaceted roles in mammalian host defense systems (1). They recognize and process antigens for T-cell presentation, release key mediators of inflammation (e.g., tumor necrosis factor), and are perhaps best characterized by their ability to endocytose and phagocytose a wide variety of molecules and cells.…”

“…They recognize and process antigens for T-cell presentation, release key mediators of inflammation (e.g., tumor necrosis factor), and are perhaps best characterized by their ability to endocytose and phagocytose a wide variety of molecules and cells. Macrophages recognize foreign substances identified by antibodies and complement (1). In addition, they can independently differentiate between self and nonself (2)(3)(4).…”

“…In addition, they can independently differentiate between self and nonself (2)(3)(4). This self-nonself discrimination may have predated the emergence of immunity mediated by lymphocytes and antibodies (1,2). The polyspecificity and selfnonself discrimination required of macrophages in primitive organisms could have been achieved by receptors with multiple or broad ligand-binding specificities (2).…”

ATP‐activated Ca2+‐permeable channels in rat peritoneal macrophages

“…Defense responses are triggered and regulated by numerous extraeellular signalling agents, such as immunoglobulins, growth factors, lymphokines etc. [1]. One of the earliest events in the stimulus-response coupling in macrophages, as in many other cell types, is Ca 2+ influx from the extracellular medium [2][3][4][5].…”

Envolvimento de sinais coestimulatórios na periodontite apical crônica em humanos

“…O reconhecimento inicial de microrganismos é mediado por receptores celulares expressos em células da imunidade inata. A interação entre moléculas de superfície do patógeno e receptores homólogos presentes na membrana celular de neutrófilos e macrófagos modulam a fagocitose e a ativação celular (GORDON et al, 1988, OHMAN et al, 1988. Portanto, monócitos, macrófagos e neutrófilos são células da imunidade inata que expressam receptores de superfície para manose, CD14, componentes do sistema complemento, porção Fc de moléculas de imunoglobulinas e receptores semelhantes a Toll (TLR, Toll-like receptor) capazes de reconhecer produtos microbianos.…”