Inflammatory Bowel Disease

Inflammatory bowel disease consists of two disorders, Crohn's disease and ulcerative colitis, in which T cellmediated inflammation causes intestinal injury. Crohn's disease is characterized by chronic inflammation and destruction of the intestinal wall, with frequent formation of fistulas. In ulcerative colitis, the lesions are largely confined to the mucosa and consist of ulcers with underlying foci of inflammation. The pathogenesis of inflammatory bowel disease was described in Chapter 13....

Defects in B Cell Differentiation Common Variable Immunodeficiency

Common variable immunodeficiency is a group of heterogeneous disorders defined by reduced levels of serum Ig, impaired antibody responses to infection or vaccines, and increased incidence of infections. The diagnosis is usually one of exclusion when other primary immunodeficiency diseases are ruled out. The presentation and pathogenesis are, as the name implies, highly variable. Although Ig deficiency and associated pyogenic infections, typically with Haemophilus influenzae and Streptococcus...

Rheumatoid Arthritis

Rheumatoid Arthritis Immunology

Rheumatoid arthritis (RA) is an inflammatory disease involving small and large joints of the extremities, including fingers, shoulders, elbows, knees, and ankles. The External triggers (e.g., UV radiation) Defective clearance of apoptotic bodies Increased burden of nuclear antigens Antinuclear antibody, antigen-antibody TLR engagement of nuclear antigen in endosomes Antinuclear antibody, antigen-antibody FIGURE 18-9 A model for the pathogenesis of systemic lupus erythematosus (SLE). In this...

Selected Readings

Annual Review Immunology

Boyman O, S Letourneau, C Krieg, and J Sprent. Homeostatic proliferation and survival of naive and memory T cells. European Journal of Immunology 39 2088-2094, 2009. Jenkins MK, HH Chu, JB McLachlan, and JJ Moon. On the composition of the pre-immune repertoire of T cells specific for peptide-major histocompatibility complex ligands. Annual Review of Immunology 28 275-294, 2010. Von Andrian UH, and CR Mackay. T-cell function and migration. New England Journal of Medicine 343 1020-1034, 2000....

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Molecular Immunology

T and B cell responses to self antigens (including antigens in joint tissues) Lymphocytes, antibodies and immune complexes enter joint FIGURE 18-10 A model for the pathogenesis of rheumatoid arthritis. According to this hypothesis, citrullinated proteins induced by environmental stimuli elicit T cell and antibody responses in genetically susceptible individuals. The T cells and antibodies enter joints, respond to the self proteins, and cause tissue injury mainly by cytokine secretion and...

Pathogenesis of Immune Complex Mediated Diseases

Antigen-antibody complexes are produced during normal immune responses, but they cause disease only when they are produced in excessive amounts, are not efficiently cleared, and become deposited in tissues. The amount of immune complex deposition in tissues is determined by the nature of the complexes and the characteristics of the blood vessels. Small complexes are often not phagocytosed and tend to be deposited in vessels more than large complexes, which are usually cleared by phagocytes....

Immune Complex Mediated Diseases

Graves Disease Antibodies

Immune complexes that cause disease may be composed of antibodies bound to either self antigens or foreign antigens. The pathologic features of diseases caused by immune complexes reflect the site of immune complex deposition and are not determined by the cellular source of the antigen. Therefore, immune complex-mediated diseases tend to affect multiple tissues and organs, although some are particularly susceptible, such as kidneys and joints. The occurrence of diseases caused by immune...

Info

Apcs And Costimulators

The known B7 family ligands expressed on APCs and CD28 family receptors expressed on T cells are shown, with their expression patterns and likely major functions. Other inhibitory receptors have been defined, such as BTLA, but these are not homologous to CD28 and are therefore not shown here. FIGURE 9-5 The B7 and CD28 families. The known B7 family ligands expressed on APCs and CD28 family receptors expressed on T cells are shown, with their expression...

Halflife of Antibodies

Recycling Endosome

Different antibody isotypes have very different half-lives in circulation. IgE has a very short half-life of about 2 days in the circulation although cell-bound IgE associated with the high-affinity IgE receptor on mast cells has a very long half-life see Chapter 19 . Circulating IgA has a half-life of about 3 days, and circulating IgM has a halflife of about 4 days. In contrast, circulating IgG molecules have a half-life of about 21 to 28 days. The long half-life of IgG is attributed to its...

Diseases Caused by Cytokine Mediated Inflammation

Th1 Mediated Damage

In immune-mediated inflammation, TH1 and TH17 cells secrete cytokines that recruit and activate leukocytes. IL-17, produced by TH17 cells, promotes neutrophil recruitment interferon-y IFN-y , produced by TH1 cells, activates macrophages and tumor necrosis factor TNF and chemokines, produced by T lymphocytes and other cells, are involved in the recruitment and activation of many types of leukocytes. Tissue injury results from the products of activated neutrophils and macrophages, such as...