title: Comparison of complement activation in vitro by different Echinococcus granulosus extracts.
abstract: In the present study we have investigated and compared in vitro the specific complement (C) activating activity of three metacestode preparations of Echinococcus granulosus. Extracts from hydatid cyst fluid (HCF-ext), protoscoleces (PSC-ext) and hydatid cyst membrane (HCM-ext) activated human C producing C3 conversion and generating the C5b6 complex and the terminal C complex (TCC). HCM-ext showed much lower C activating activity than PSC-ext and HCF-ext. Moreover, its ability to generate C5b6 and TCC was lower than its ability to convert C3. On the other hand, PSC-ext and HCF-ext proved to be good C activators when their specific C activating activities were compared with that of inulin. However, PSC-ext produced lower levels of TCC than those produced by HCF-ext, in spite of the fact that both produced practically the same levels of C3d and C5b6. These results may be consistent with the existence of several mechanisms of C modulation involved in the defence of the parasite against host C damage.
authors.affiliation: Cátedra de Immunología, Facultad de Quimica/Facultad de Ciencias, Universidad de la República, Montevidco, Uruguay.
authors.forename: F
authors.initials: F
authors.lastname: Irigoín
authors.forename: R
authors.initials: R
authors.lastname: Würzner
authors.forename: R B
authors.initials: RB
authors.lastname: Sim
authors.forename: A M
authors.initials: AM
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology; D003167:Complement Activation; D003176:Complement C3 / Q000378:metabolism; D004443:Echinococcosis / Q000276:immunology / Q000662:veterinary; D004446:Echinococcus / Q000254:growth & development / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques
chemical_list: D003176:Complement C3