Serological diagnosis of cystic echinococcosis using recombinant antigen B 8-kDa-subunits1 of Echinococcus granulosus

To obtain Echinococcus granulosus recombinant antigen B 8-kDa-subunits1 (rEgAgB8/1) through gene engineering technique and evaluate its usefulness for serodiagnosis of human cystic echinococcosis. a previously constructed rEgAgB8/1-prokaryotic expression plasmid vector (pET32b-rEgAgB8/1)was transformed into E.coli BL-21(DE3). Protein expression was induced with IPTG and the expressed rEgAgB8/1 was purified using His-tagged affinity chromatography column. Thirty-one serum samples from surgically confirmed patients with cystic echinococcosis (CE) were analyzed by serology in ELISA and immunoblotting using rEgAgB8/1 as diagnostic antigen,and the results were analyzed by retrospective studies. 28 (90.3%) of 31 serum samples were found to be positive both in rEgAgB8/1-ELISA and rEgAgB8/1-immunoblot assary,the remaining 3 sero-negative serum samples were from CE patients with single cyst in liver diagnosed for the first time. The titer of serum antibody seemed to be increased through the increase of number of hydatid cysts formed(F=5.06,P=0.0142),and the antibody level in serum samples from patients with single cyst was lower than that in with 2 and 3cysts,howere there was no apperant discrepancy of serum antibody titer between patients with 2 cysts and 3 cysts. It is apparent that rEgAgB8/1 is highly useful for serodiagnosis of human cystic echinococcosis. The titer of serum antibody against rEgAgB8/1 is higher in CE patients with multi-cysts than in with that of single cyst.