The macrophage membrane has receptors for certain classes of antibody. If an antigen is coated with the appropriate antibody, the complex of antigen and antibody binds to antibody receptors on the macrophage membrane more readily than antigen alone and phagocytosis is enhanced. Thus antibody functions as an opsonin, a molecule that binds to both antigen and phagocyte, thereby enhancing phagocytosis. The process by which opsonins render particulate antigens more susceptible to phagocytosis is called opsonization. Mast Cell - A bone-marrow-derived cell present in a variety of tissues that resembles peripheral blood basophils, bears Fc receptors for IgE, and undergoes IgE-mediated degranulation.
Mast cell precursors, which are formed in the bone marrow by hematopoiesis, are released into the blood as undifferentiated cells; they do not differentiate until they leave the blood and enter the tissues. Mast cells can be found in a wide variety of tissues, including the skin, connective tissues of various organs, and mucosal epithelial tissue of the respiratory, genitourinary, and digestive tracts. Like circulating basophils, these cells have large numbers of cytoplasmic granules that contain histamine and other pharmacologically active substances. Tissue mast cells are related to but distinct from, basophils. Mast cells play an important role in the development of allergies. Mast cells increased numbers during allergies.
Mast cell precursors, which are formed in the bone marrow by hematopoiesis, are released into the blood as undifferentiated cells; they do not differentiate until they leave the blood and enter the tissues. Mast cells can be found in a wide variety of tissues, including the skin, connective tissues of various organs, and mucosal epithelial tissue of the respiratory, genitourinary, and digestive tracts. Like circulating basophils, these cells have large numbers of cytoplasmic granules that contain histamine and other pharmacologically active substances. Tissue mast cells are related to but distinct from, basophils. Mast cells play an important role in the development of allergies. Mast cells increased numbers during allergies.
References: Kuby Immunology 6th Edition. Pictures are directly linked to websites.
Personal Feedback: I confused these two words, opsonin and mast cell; therefore I wanted to study little more and make sure I really know about these words of Immunology.
Written by D.J. Kim
