APIH223885223 - CME/CMLE - Overview of the Development of Monocytes & Macrophages-APIH223885223

APIH223885223 - Educational Activity

Pdf Summary

This educational commentary, provided by Sergey V. Smirnov from Asante Three Rivers Medical Center, offers an in-depth overview of the development and function of monocytes and macrophages within the immune system. The document, affiliated with the American Society for Clinical Pathology (ASCP), aims to educate participants on several key aspects of the mononuclear phagocyte system (MPS).<br /><br />**Historical Context**: The mononuclear phagocyte system's concept dates back to Russian scientist Elie Metchnikoff, who discovered phagocytosis and emphasized the role of leukocytes in immune responses.<br /><br />**Terminology, Development, and Morphology**: Monocytes originate in the bone marrow and circulate in the blood before maturing into macrophages in tissues. They vary in size and morphology based on their location and activation status, transforming from monocytes into specialized macrophages such as microglial cells in the CNS, Kupffer cells in the liver, and osteoclasts in bones.<br /><br />**Functions**: Monocytes and macrophages are crucial for phagocytosis (ingestion and destruction of pathogens), secretion of substances that modulate immune responses, and removal of cellular debris. They play significant roles in both innate and adaptive immunity by interacting with T lymphocytes and presenting antigens, thus bridging innate and adaptive immune responses.<br /><br />**Macrophages and Viral Infections**: Macrophages can serve as reservoirs for viruses like HIV, contributing to the pathogenesis and progression of viral infections. These cells can be infected but are relatively resistant to viral destruction, allowing them to harbor viruses and facilitate infection of T cells.<br /><br />**Noninflammatory Conditions**: The fate of monocytes in the absence of inflammation is uncertain, though some may turn into macrophages or be disposed of in unknown ways.<br /><br />**Conclusion**: The MPS plays a vital role in immune defense against pathogens. Ongoing research is essential to understand and enhance the immune functions of mononuclear phagocyte cells, especially in viral infections.

Keywords

monocytes

macrophages

immune system

phagocytosis

mononuclear phagocyte system

Elie Metchnikoff

viral infections

innate immunity

adaptive immunity

bone marrow