Flow Cytometry Based Assessment of Innate Immune Function Using Phagocytosis and Reactive Oxygen Species Measurement

Authors: Jayne Schaubhut, Rubina Pal, Darcey L. Clark, Lynette Brown, and Jennifer J Stewart
Flow Contract Site Laboratory, LLC

Abstract: The immune system is in a constant battle to stave off and outmaneuver pathogenic invaders. One ancient strategy used by innate immune cells is to simply engulf and eat the invaders, a process called phagocytosis. Specialized cells called phagocytes include monocytes, macrophages, neutrophils, dendritic cells, osteoclasts, and eosinophils. Phagocytosis begins with the binding of opsonins (i.e. complement or antibody) and/or specific molecules on the pathogen’s cell surface (pathogen-associated molecular patterns or PAMPs) to cell surface receptors on the phagocyte. Opsinic receptors on phagocytes are Fc Receptors (FcR) and complement receptors (CR). Non-opsinic receptors on phagocytes include pattern recognition receptors (PPR), such as Toll-Like Receptors (TLR). Reactive Oxygen Species (ROS) generated during phagocytosis, (known as the Respiratory Burst), are crucial to the destruction of pathogens by the phagocyte. Phagocytosis is an important indicator of overall innate immune cell function. Some drugs can effect innate immune cells, and put subjects at risk for infection.