Two different 8 kDa monomers are involved in the oligomeric organization of the native <i>Echinococcus granulosus</i> antigen B

González, Gabriel Alcántar; Nieto, Alberto; Fernández, Cecilia; Örn, Anders; Wernstedt, Christer; Hellman, Ulf

doi:10.1046/j.1365-3024.1996.d01-38.x

Cited by 63 publications

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“…This fact confirms that AgB is present in the metacestode of the parasite, but not in the adult stage. Similarly, the polypeptide of 20-24 kDa may correspond to subunits of Ag 5 or Ag B, and the component of 41 kDa may match the major subunit of Ag 5 (Lightowlers et al 1989, Ortona et al 1995, González et al 1996. Some of the products identified in HCF by the pool of human sera in the present study may correspond to those previously described by other authors using the same antigenic extract.…”

Section: Discussionsupporting

confidence: 80%

Shared and non-shared antigens from three different extracts of the metacestode of Echinococcus granulosus

Carmena

Martı́nez

Benito

et al. 2005

Mem. Inst. Oswaldo Cruz

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Section: Discussionsupporting

confidence: 80%

Shared and non-shared antigens from three different extracts of the metacestode of Echinococcus granulosus

Carmena

Martı́nez

Benito

et al. 2005

Mem. Inst. Oswaldo Cruz

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“…Antibodies-The monoclonal antibodies used in this study, mAbs EB7, AB10, EG9, and BG10, have been described before (2). All four mAbs react with the AgB8/1 subunit of AgB or the native antigen but not with the AgB8/2 subunit.…”

Section: Methodsmentioning

confidence: 99%

“…AgB and Peptides-AgB was purified to homogeneity from hydatid cyst fluid as described before (2). Recombinant AgB8/1 was a kind gift from Dr. Arnaldo Zaha.…”

Section: Methodsmentioning

confidence: 99%

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Identification of Critical Residues of an Immunodominant Region of Echinococcus granulosus Antigen B

González‐Sapienza

Cachau

2003

Journal of Biological Chemistry

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Immune evasion strategies often shape the immunogenicity of parasite components. We recently found that the N-terminal extension of the major subunit of Echinococcus granulosus antigen B (AgB), the causative agent of hydatid disease, concentrates the immunoreactive B cell epitopes of the native molecule. The nature of this immunodominance was analyzed using four monoclonal antibodies (mAbs) defining overlapping epitopes in this region of the AgB molecule. The minimal epitope requirements of these mAbs were determined using phage display peptide libraries. The consensus sequences isolated with the mAbs, and alanine replacement analysis with synthetic peptides mapped the relevant molecular contacts within a short stretch corresponding to residues 17-24 of the AgB major subunit. Substitution of two critical residues within this stretch produced a dramatic loss of antigenicity, as determined by using patient sera. The circular dichroism spectra of the antigen, together with the distribution of the contact residues, suggest that this region adopts an amphipathic ␣-helix structure that clusters the contact residues on its polar side. To provide further insight in the interpretation of the structure activity relationships for this immunoreactive region of E. granulosus AgB, we developed a model for the N-terminal extension of the AgB major subunit, which helps to rationalize our data.Antigen B (AgB), 1 the major antigens of Echinococcus granulosus, the causative agent of cystic hydatid disease, is a 120-kDa protein composed of multimers of homologous but different 8-kDa subunits (AgB8/1, AgB8/2, and AgB8/3) (1-3). The antigen is present in large amounts in the metacestode cyst fluid, and its biological functions suggest that it may play a relevant role in the host/parasite interaction. AgB has been reported as a protease inhibitor that impairs the recruitment of polymorphonuclear cells and skews the Th1/Th2 cytokine ratio toward an immunopathology-associated Th2 polarization (4, 5). In human infections, AgB is highly immunogenic, which has prompted its use as a diagnostic reagent. In fact, AgB possesses the highest diagnostic value among the major E. granulosus antigens (6), and we have found that p176, a 38-mer synthetic peptide representing the N-terminal extension of AgB8/1, exhibits higher diagnostic sensitivity and specificity than native AgB (7). This is a singular finding considering that, in general, synthetic peptides are poor mimics of the parent epitope and, accordingly, exhibit low diagnostic sensitivities. There are several reasons for this. First, the full group of contact atoms of a given antibody/antigen interface are seldom derived from a short linear stretch of the antigen (8); second, the structural conformation of peptides is not restricted in solution, and there is therefore an unfavorable entropic component to the binding (9). In addition, a single peptide mimics a partial region of the parent protein and, consequently, only a fraction of the polyclonal antibody response against the native antigen...

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“…AgB was extracted from HF by anion exchange chromatography by using DEAE-sepharose fast flow (Sigma, USA) as the method described by Gonzalez et al [12] with minor modifications.…”

Section: Antigen B Purificationmentioning

confidence: 99%

Efficiency Evaluation of Immunization Protocol with Echinococcus Granulosus Antigen B (Agb)

Mustafa¹,

Shani²

2017

Cihan Univ.-Erbil Sci. J.

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Antigen B (AgB), the major antigens of Echinococcus granulosus, is a polymeric thermostable lipoprotein that constitutes as much as 10% of hydatid fluid.Antibody and cytokine response were both studied in rabbits immunized with Echinococcus granulosus antigen B (AgB). This study aimed to assess the effect of antigen B (AgB) on immune response for this purpose hydatid cysts were collected from liver of infected sheep from slaughter house in Basra . AgB was purified from hydatid fluid by anion exchange chromatography.For evaluation of AgB efficiency in immunization , 15 rabbits were enrolled in the study ,10 of them were immunized subcutaneously with AgB using freund's complete adjuvant after two weeks three booster injections were repeated intramuscularly according to immunization schedule using freund's incomplete adjuvant and 5 rabbits were treated as a control group. After six weeks , blood were collected from rabbits and the levels of IgG , IFN-γ and IL-10 were measured by ELISA test.Means of IgG of immunized rabbits were significantly (P < 0.05) elevated (45.9) ng/ml in comparison with control rabbits (16.6) ng/ml. Cytokines levels of Th1 (IFN-γ) and Th2 (IL-10) were recorded a significant differences (P < 0.05) between immunized and control groups , the mean concentrations of IFN-γ in immunized rabbits (28.6 pg/ml) was lower than those of control group (83.6 pg/ml) while IL-10 mean concentrations in immunized rabbits (60.1) pg/ml was higher than those of control group (18.8) pg/ml .The results indicated that AgB has the ability to modulate immune response toward Th2 bias in immunized rabbits as there was significant elevation in total IgG, IL-10 and significant decreasing IFN-γ concentration.

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Two different 8 kDa monomers are involved in the oligomeric organization of the native Echinococcus granulosus antigen B

Cited by 63 publications

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Shared and non-shared antigens from three different extracts of the metacestode of Echinococcus granulosus

Shared and non-shared antigens from three different extracts of the metacestode of Echinococcus granulosus

Identification of Critical Residues of an Immunodominant Region of Echinococcus granulosus Antigen B

Efficiency Evaluation of Immunization Protocol with Echinococcus Granulosus Antigen B (Agb)

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