Eosinophil granular proteins

The effector role of the eosinophil in the pathogenesis of asthma is mediated in part by the release of eosinophil-specific granular proteins. The four principal basic proteins in the secondary granules of the eosinophil are MBP, EPO, ECP and EDN. 

Some members of the human RNase A superfamily of proteins are known to have host defense activities (reviewed in ref. 9). These include, for example, two of the eosinophil cytotoxic granular proteins, eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin (EDN) (10). Angiogenin, a protein 65 % homologous to pancreatic RNase (11,12) that was originally isolated on the basis of its angiogenic activity (13), is a potent inhibitor of protein synthesis in the rabbit reticulocyte lysate (14) and when injected into Xenopus oocytes (15). We have therefore sought to fuse RNases to MAbs to evaluate their usefulness as immunotoxins (16,17). 

Eosinophilic granular bodies (EGB) are eosinophilic droplets of protein often found in pilocytic astrocytomas. 

Leff, A.R. Herrnreiter, A. Naclerio, R.M. Baroody, F.M. Handley, D.A. Munoz, N.M. Effect of enantiomeric forms of albuterol on stimulated secretion of granular protein from human eosinophils. Pulm. Pharmacol. Ther. 1997, 10, 97-104. 

Figure 5.9. The destruction of parasites by eosinophils. Eosinophils bind to opsonized parasites via IgE-Fc receptors expressed on their surface. Binding induces release of granular contents by exocytosis. Major basic protein, the most abundant granular-derived protein, then initiates destruction of the parasite by lysis...

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