STUDY OF THE IN-VITRO ACTIVATION OF THE COMPLEMENT ALTERNATIVE PATHWAY BY ECHINOCOCCUS-GRANULOSUS HYDATID CYST FLUID

In the present study we have investigated the fluid phase activation o f the complement (C) alternative pathway by Echinococcus granulosus sh eep hydatid cyst fluid (SHCF) and its higher molecular weight fraction (SHCF-I) by quantitating the formation of both the terminal C interme diary C5b6 complex and the terminal C complex (TCC). Our results show that in vitro C activation progresses beyond the C5 step suggesting th at potentially lytic complexes may be generated in vivo. In addition, SHCF and SHCF-I glucidic moieties are probably involved in C activatio n since 80% and 86% of SHCF and SHCF-I activity respectively was destr oyed by periodate oxidation. Furthermore, partial deglycosylation with Peptide N-Glycosidase F of SHCF-I which had been digested with Pronas e E, released an active fl action (MW <14 KDa) which bound to Soybean agglutinin, suggesting that N-linked oligosaccharides containing alpha - or beta-linked N-acetyl galactosamine play a role in C activation by SHCF.