Differential serodiagnosis for cystic and alveolar echinococcosis using fractions of Echinococcus granulosus cyst fluid (antigen B) and E. multilocularis protoscolex (EM18).

Abstract

Abstract. Echinococcus granulosus cyst fluid and E. multilocularis protoscolex extract were fractionated by a single step of preparative isoelectric focusing, resulting in an antigen B-rich fraction (8-kD) and an Em18-rich fraction, respectively. The usefulness of both fractions for differential serodiagnosis of cystic (CE) and alveolar (AE) echinococcosis was evaluated by a large-scale immunoblot analysis on a battery of 354 serum samples. These included 66 from AE patients originating from four different endemic areas, 173 from CE patients originating from seven different endemic areas, 71 from patients with other parasitic diseases, 15 from patients with hepatomas, and 29 from healthy individuals. In an immunoblot with the antigen B-rich fraction, 92% (158 of 173) of the CE sera as well as 79% (52 of 66) of the AE sera reacted with the 8-kD subunit. No cross-reactivity occurred with any sera from patients with cysticercosis, other parasitic diseases, or with hepatomas, or from healthy controls. In an immunoblot with the Em18-rich fraction, all but two sera from AE patients (64 of 66, 97%) recognized Em18, and only nine of 34 CE sera from China reacted with it. All other (139) CE sera from six other countries were negative as were all (115) other non-echinococcosis sera. These findings indicate that antigen B (8-kD) is not species-specific for E. granulosus but is genus-specific for Echinococcus, and that the Em18 antigen is a reliable serologic marker for species-specific differentiation of AE from CE.Echinococcosis, one of the most lethal parasitic zoonoses, remains a public health problem of worldwide importance and has recently gained recognition in some regions as an emerging or re-emerging disease.

Pulmonary echinococcosis

“…These antigens can discriminate between E. granulosus and E. multilocularis in 95-97% of cases [77][78][79][80].…”

Analysis of cyst fluid antigens from different hosts for the serodiagnosis of hydatidosis

“…Eight and 24 kDa antigens were also detected and accepted as specific in this study. As described in previous reports (7,14,15), the smallest subunit of antigen B (8 kDa) is highly sensitive and is expected to be Echinococcus genus specific (7). Our immunoblotting results, obtained with cyst fluid from sheep and donkey indicated that all the sera of mice infected secondary hydatidosis reacted with the antigen B subunit (8 kDa) in cyst fluid.…”

“…Antigenic profiles of protoscolices, fluid and germinal layer of cyst hydatids were studied by Western blotting in many studies and got different results due to host differences (5,6,7,13,16). In general hydatid cyst fluid (HCF) is collected from naturally infected intermediate hosts such as sheep, cattle, horses, camels, pigs or moose or from CE patients for preparation of purified native antigens (5,6,7,13,14). However, the nature and quality of the antigens are variable among the host species (12,15).…”

Evaluation of the Diagnostic Value of the ELISA Tests Developed by Using EgHF, Em2 and EmII/3-10 Antigens in the Serological Diagnosis of Alveolar Echinococcosis

“…Serolojik testler, AE'nin tanısında, E.granulosus'un neden olduğu kistik ekinokokkoz (KE)'a kıyasla daha güvenilir olmaktadır. KE tanısında kullanılan Ag5 ve AgB antijenlerinin, diğer parazitlerin benzer molekülleriyle ortak epitoplara sahip olmasından ve KE hastalarının büyük oranının tüm majör E.granulosus antijenlerine karşı seronegatif olmasından dolayı, KE'nin serolojik tanısı AE'deki kadar özgül ve duyarlı olmamaktadır 11 . AE tanısında kullanılan testlerin duyarlılığı %82-97 arasında olup, saflaştırılmış ve/veya rekombinant özgül antijenler kullanıldığında özgüllüğü oldukça yüksek (%94-100) düzeylere ulaşmaktadır 12,13 .…”