Mast cell antigen-antibody complex

A cascade of proteins of the immune response that can be triggered by antigen-antibody complexes and by the innate immune system (e.g. exposure to microbial polysaccharides) to raise the immune response. Complement proteins can detect and bind to foreign material or immune complexes and label them for phagocytosis. They can also cause inflammation by directly degranulating mast cells and releasing chemokines to recruit other immune cells into the affected area. 

The formation of antigen-antibody complexes can lead to clinical syndromes such as the Arthus reaction. In this model, a high level of preformed specific IgG antibody combines with antigen to produce a localized edematous, erythematous reaction within 5 to 8 hours. The reaction involves local formation of insoluble antigen-antibody complexes, complement activation with release of C3a and C5a collectively referred to as anaphylatoxins, mast cell degranulation, and influx of polymorphonuclear cells. 

PARISH, W.E. (1972) Eosinophilia cutaneous eosinophilia in guinea pigs mediated by passive anaphylaxis with IgGl or reagin, and antigen-antibody complexes its relation to neutrophils and mast cells. Immunology, 23, 19-34. 

Illustrated in Figure 3 is a likely over-all mechanistic role of theophylline in asthma. Extrinsic or immediate hypersensitivity-type asthma begins with an antigen -antibody complex at mast cells and results in the release of chemical mediators which affect cells in airways. Smooth muscle cells contract, capillaries leak, and secretory cells hypersecrete to give a triad of bronchospasm, edema and Increased mucous, respectively. Shown is the two-enzyme... 

The interaction of antibody-antigen complexes with cells of the immune system results in the activation of a variety of responses ranging from ADCC, mast-cell degranulation, lymphocyte proliferation, antibody secretion and phagocytosis. All these processes are activated via the binding of the Fc domain of the antibody molecule, which is exposed during antibody-... 

Must histamine is synthesized and stored in mast cells and basophilic granultKytes. Protein-complexed histamine is then stored in secretory granules and released by exocytosis in le.sponse to a wide variety of immune (antigen and antibody) and nonimmunc (bacterial products, xenobiotics, physical effects, and cholinergic effects) stimuli. The release of histamine as one of the mediators of hypersensitivity reactions is initiated by the interaction of an antigen-IgE com-... 

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