phagocyte

(noun)

A cell of the immune system, such as a neutrophil, macrophage or dendritic cell, that engulfs and destroys viruses, bacteria and waste materials, or in the case of mature dendritic cells; displays antigens from invading pathogens to cells of the lymphoid lineage.

Related Terms

Examples of phagocyte in the following topics:

  • Phagocyte Migration and Phagocytosis

    • The phagocyte then stretches itself around the bacterium and engulfs it.
    • Once inside the phagocyte, the bacterium is trapped in a compartment called a phagosome.
    • This debris serves as a signal to recruit more phagocytes from the blood.
    • All phagocytes, and especially macrophages, exist in degrees of readiness.
    • Chemotaxis is the process by which phagocytes follow the cytokine "scent" to the infected spot.

  • Direct Damage

    • Phagocytosis is a process utilized by phagocytes (white blood cells) as a defense mechanism to protect from foreign bodies.
    • The phagocytes engulf invaders and present them to additional factors within the immune system that result in their destruction.
    • Pathogens that exhibit the ability to avoid contact utilize various processes to accomplish this, including: the ability to grow in regions of the body where phagocytes are incapable of reaching; the ability to inhibit the activation of an immune response; inhibiting and interfering with chemotaxis which drives the phagocytes to site of infection; and 'tricking' the immune system to identify the bacteria as 'self. ' Additional mechanism(s) by which bacteria can avoid destruction is by avoiding engulfment.
    • This is accomplished by the ability of the bacteria to exhibit produce molecules that interfere with the phagocytes ability to internalize the bacteria.

  • Type IV (Delayed Cell-Mediated) Reactions

    • Cell-mediated immunity is an immune response that does not involve antibodies, but rather involves the activation of phagocytes, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.
    • Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells.

  • Whooping Cough

    • The end result is that phagocytes convert too much ATP to cyclic AMP, which can cause disturbances in cellular signaling mechanisms.
    • This prevents phagocytes from correctly responding to an infection.

  • The Complement System

    • The complement system helps or "complements" the ability of antibodies and phagocytic cells to clear pathogens from an organism.
    • The complement system helps or "complements" the ability of antibodies and phagocytic cells to clear pathogens from an organism.
    • C3b binds to the surface of pathogens, leading to greater internalization by phagocytic cells by opsonization.

  • Cells and Organs of the Immune System

    • The innate leukocytes include the phagocytes, mast cells, eosinophils, basophils, and natural killer cells.
    • Neutrophils and macrophages are phagocytes that travel throughout the body in pursuit of invading pathogens.
    • Neutrophils are normally found in the bloodstream and are the most abundant type of phagocyte.
    • Dendritic cells are phagocytes in tissues that are in contact with the external environment, and are located mainly in the skin, nose, lungs, stomach, and intestines.

  • The Complement System

    • The complement system helps antibodies and phagocytic cells clear pathogens from an organism.

  • Primary Immunodeficiency Diseases

    • Tests for phagocyte function: reduction of nitro blue tetrazolium chloride, assays of chemotaxis, bactericidal activity
    • Phagocytes are the cells that engulf and ingest pathogens (phagocytosis), and destroy them with chemicals.
    • In certain conditions, either the number of phagocytes is reduced or their functional capacity is impaired.

  • Dendritic Cells

    • Most, called myeloid dendritic cells, are related in lineage to mononuclear phagocytes.

  • Other Fungi Involved in Respiratory Disease

    • Cytologic preparation from a case of feline sporotrichosis; phagocytic cells show numerous variably-shaped yeast forms within.