Leukocyte Migration and Inflammation CHAPTER 15 353 VISUALIZING CONCEPTS Prostaglandins = Fever (via pituitary) ACTH Adrenal cortex Corticosteroids IL-1 TNF-cx Acute-phase proteins inflammatory response IL-6, LIF, OSM Serum amyloid A(SAA) Liver Leukocytosis (个 white blood cells Bone marrow (个 CSF by stromal cells and FIGURE 15-13 Overview of the organs and mediators involved tion, are particularly important in mediating acute-phase effects in a systemic acute-phase response. IL-1, IL-6, and TNF-a, which LIF= leukemia inhibitory factor; OSM= oncostatin M are produced by activated macrophages at the site of inflamma- chronically activated macrophages also stimulate fibroblast Roles of IFN-y and TNF-a in Chronic proliferation and collagen production. a type of scar tissue Inflammation develops at sites of chronic inflammation by a process called fibrosis, a wound-healing reaction that can interfere with nor- Two cytokines in particular, IFN-y and TNF-cx, play a central mal tissue function. Chronic inflammation may also lead to role in the development of chronic inflammation. THl cells, formation of a granuloma, a tumor-like mass consisting of a NK cells, and Tc cells release IFN-y, while activated macro- central area of activated macrophages surrounded by activated phages secrete TNF-c lymphocytes. The center of the granuloma often contains Members of the interferon family of glycoproteins(IFN-c multinucleated giant cells formed by the fusion of activated and IFN-B) are released from virus-infected cells and confer macrophages. These giant cells typically are surrounded by antiviral protection on neighboring cells. Exactly which inter large modified macrophages that resemble epithelial cells and feron is produced depends on the type of cell infected IFN-c therefore are called epithelioid cells is produced by leukocytes, IFN-B, often called fibroblastchronically activated macrophages also stimulate fibroblast proliferation and collagen production. A type of scar tissue develops at sites of chronic inflammation by a process called fibrosis, a wound-healing reaction that can interfere with nor￾mal tissue function. Chronic inflammation may also lead to formation of a granuloma, a tumor-like mass consisting of a central area of activated macrophages surrounded by activated lymphocytes. The center of the granuloma often contains multinucleated giant cells formed by the fusion of activated macrophages. These giant cells typically are surrounded by large modified macrophages that resemble epithelial cells and therefore are called epithelioid cells. Roles of IFN- and TNF- in Chronic Inflammation Two cytokines in particular, IFN- and TNF-, play a central role in the development of chronic inflammation. TH1 cells, NK cells, and TC cells release IFN-, while activated macro￾phages secrete TNF-. Members of the interferon family of glycoproteins (IFN- and IFN-) are released from virus-infected cells and confer antiviral protection on neighboring cells. Exactly which inter￾feron is produced depends on the type of cell infected. IFN- is produced by leukocytes, IFN-, often called fibroblast Leukocyte Migration and Inflammation CHAPTER 15 353 VISUALIZING CONCEPTS Prostaglandins Acute-phase proteins: C-reactive protein (CRP) Serum amyloid A (SAA) Fibrinogen Mannose-binding protein Complement components Fever Bone marrow ( CSF by stromal cells and macrophages) Leukocytosis ( white blood cells) ACTH (via pituitary) Local acute inflammatory response Corticosteroids IL-1, TNF-α IL-6, TNF-α IL-6, LIF, OSM IL-1, TNF-α, Il-6 Liver Hypothalamus Adrenal cortex FIGURE 15-13 Overview of the organs and mediators involved in a systemic acute-phase response. IL-1, IL-6, and TNF-, which are produced by activated macrophages at the site of inflamma￾tion, are particularly important in mediating acute-phase effects. LIF = leukemia inhibitory factor; OSM = oncostatin M.