USEFULNESS OF RECOMBINANT ANTIGEN B4 FOR SERODIAGNOSIS OF HYDATID DISEASE

MUZULIN PM; RODRIGUEZ M; IRAZU L; ROSENZVIT MC

Congreso; XXIII INTERNATIONAL CONGRESS OF HYDATOLOGY; 2009

USEFULNESS OF RECOMBINANT ANTIGEN B4 FOR SERODIAGNOSIS OF HYDATID DISEASE MUZULIN P1, RODRIGUEZ M1, IRAZU L1 and ROSENZVIT M.2 1 Departamento de Parasitología, INEI- ANLIS Dr. “Carlos G. Malbrán”, Buenos Aires, Argentina. 2 Departamento de Microbiología, Facultad de Medicina, Universidad de Buenos Aires, Argentina. pmuzulin@anlis.gov.ar               Currently, 10 strains of the cestode parasite Echinococcus granulosus are known. The sheep, Tasmanian sheep, cattle, camel and pig strains were found in Argentina. Antigen B (AgB), one of the major antigens of cystic hydatid fluid (CHF), is encoded by a family of 5 genes: EgAgB1-5. Our previous results suggested that the expression of AgB genes differed among strains. In order to evaluate the diagnostic performance of AgB4, which is present at the genomic and transcriptional levels in the strains identified in Argentina, a cDNA encoding this antigen was expressed in Escherichia coli. The diagnostic value of recombinant AgB4 (rB4) was evaluated using an ELISA assay standardized by the Hydatidic Serology South American Network. Three antigens were compared: rB4, CHF from ovine (oCHF) and porcine (pCHF) cysts. The human sera collection comprised 76 samples from patients with surgically confirmed cystic hydatid disease, 31 sera from healthy donors and sera from patients with the following diseases: trichinellosis (n=2), fascioliasis (n=6), cysticercosis (n=23), schistosomiasis (n=6) and alveolar hydatid disease (n=10). The cutoff value was established by Receiver Operating Characteristic Analysis (ROC). rB4 showed a better Global Efficiency (84.5%), than oCHF (83.2%) and pCHF (81.9%). The sensitivity values obtained with the antigens were 75%, 84.2% and 84.2% for the B4r, oCHF and pCHF respectively. The specificities obtained were 93.7% (rB4), 82.3% (oCHF) and 79.7% (pCHF). The high secificity of rB4, that was negative even for the alveolar hydatid disease sera tested, makes if suitable for the confirmatory diagnosis of hydatid disease.   Key Words: strains, Antigen B, recombinant antigen, ELISA.