Innate Defenses

TABLE 22.1 Summary of Innate Defenses COMPONENT FUNCTIONS SECOND LINE OF DEFENSE: INTERNAL DEFENSES Antimicrobial Substances lnterferons (IFNs) Complement system Iron-binding proteins Antimicrobial proteins (AMPs) Natural killer (NK) cells Phagocytes Inflammation Fever Protect uninfected host cells from viral infection. Causes cytolysis of microbes; promotes phagocytosis; contributes to inflammation. Inhibit growth of certain bacteria by reducing amount of available iron. Have broad-spectrum antimicrobial activities and attract dendritic cells and mast cells. Kill infected target cells by releasing granules that contain perforin and granzymes; phagocytes then kill released microbes. Ingest foreign particulate matter. Confines and destroys microbes; initiates tissue repair. Intensifies effects of interferons; inhibits growth of some microbes; speeds up body reactions that aid repair.