Abstract
Background: Several tools have been proposed for serodiagnosis of cystic echinococcosis (CE), but none seems promising for cyst viability assessment. Antigens with stage-specific diagnostic value have been described, but few studies with well-characterized antigens and human serum samples have been performed. Antigen B (AgB) proteoforms hold promise as markers of viability, due to their differential stage-related expression and immunoreactivity. Methods: Four AgB subunits (AgB1, AgB2, AgB3, AgB4) were synthesized and structurally characterized. Based on the preliminary evaluation of the subunits by western immunoblotting and enzyme-linked immunosorbent assay (ELISA), AgB1 and AgB2 were further tested in two ELISA setups and extensively validated on 422 human serum samples. Results: All subunits showed a high degree of spontaneous oligomerization. Interacting residues within oligomers were identified, showing that both the N-terminal and C-terminal of each subunit are involved in homo-oligomer contact interfaces. No hetero-oligomer was identified. AgB1 and AgB2 ELISAs revealed different sensitivities relative to cyst stage. Of note, besides high specificity (97.2%), AgB1 revealed a higher sensitivity for active-transitional cysts (100% for CE1, 77.8% for CE2, 81.5% for CE3a, and 86.3% for CE3b) than for inactive cysts (41.7% for CE4 and 11.1% for CE5) and postsurgical patients (44%). Interestingly, 19 of 20 patients with spontaneously inactive cysts and 6 of 9 treated with albendazole >5 years earlier were negative on the AgB1 assay. Conclusions: The structural characterization of subunits provides insights into the synthetic antigen conformation. The stage-related sensitivity of synthetic AgB1 holds promise as part of a multiantigen setting and deserves further longitudinal evaluation as marker of cyst viability.
| Original language | English |
|---|---|
| Pages (from-to) | 1342-1351 |
| Number of pages | 10 |
| Journal | Clinical Infectious Diseases |
| Volume | 66 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - May 1 2018 |
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Keywords
- AgB
- Cyst viability
- Cystic echinococcosis
- Immunological characterization
- Serodiagnosis
- Structural
ASJC Scopus subject areas
- Microbiology (medical)
- Infectious Diseases
Cite this
Structural and immunodiagnostic characterization of synthetic antigen B subunits from echinococcus granulosus and their evaluation as target antigens for cyst viability assessment. / Pagnozzi, Daniela; Tamarozzi, Francesca; Roggio, Anna Maria; Tedde, Vittorio; Addis, Maria Filippa; Pisanu, Salvatore; Masu, Gabriella; Santucciu, Cinzia; Vola, Ambra; Casulli, Adriano; Masala, Giovanna; Brunetti, Enrico; Uzzau, Sergio.
In: Clinical Infectious Diseases, Vol. 66, No. 9, 01.05.2018, p. 1342-1351.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structural and immunodiagnostic characterization of synthetic antigen B subunits from echinococcus granulosus and their evaluation as target antigens for cyst viability assessment
AU - Pagnozzi, Daniela
AU - Tamarozzi, Francesca
AU - Roggio, Anna Maria
AU - Tedde, Vittorio
AU - Addis, Maria Filippa
AU - Pisanu, Salvatore
AU - Masu, Gabriella
AU - Santucciu, Cinzia
AU - Vola, Ambra
AU - Casulli, Adriano
AU - Masala, Giovanna
AU - Brunetti, Enrico
AU - Uzzau, Sergio
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Background: Several tools have been proposed for serodiagnosis of cystic echinococcosis (CE), but none seems promising for cyst viability assessment. Antigens with stage-specific diagnostic value have been described, but few studies with well-characterized antigens and human serum samples have been performed. Antigen B (AgB) proteoforms hold promise as markers of viability, due to their differential stage-related expression and immunoreactivity. Methods: Four AgB subunits (AgB1, AgB2, AgB3, AgB4) were synthesized and structurally characterized. Based on the preliminary evaluation of the subunits by western immunoblotting and enzyme-linked immunosorbent assay (ELISA), AgB1 and AgB2 were further tested in two ELISA setups and extensively validated on 422 human serum samples. Results: All subunits showed a high degree of spontaneous oligomerization. Interacting residues within oligomers were identified, showing that both the N-terminal and C-terminal of each subunit are involved in homo-oligomer contact interfaces. No hetero-oligomer was identified. AgB1 and AgB2 ELISAs revealed different sensitivities relative to cyst stage. Of note, besides high specificity (97.2%), AgB1 revealed a higher sensitivity for active-transitional cysts (100% for CE1, 77.8% for CE2, 81.5% for CE3a, and 86.3% for CE3b) than for inactive cysts (41.7% for CE4 and 11.1% for CE5) and postsurgical patients (44%). Interestingly, 19 of 20 patients with spontaneously inactive cysts and 6 of 9 treated with albendazole >5 years earlier were negative on the AgB1 assay. Conclusions: The structural characterization of subunits provides insights into the synthetic antigen conformation. The stage-related sensitivity of synthetic AgB1 holds promise as part of a multiantigen setting and deserves further longitudinal evaluation as marker of cyst viability.
AB - Background: Several tools have been proposed for serodiagnosis of cystic echinococcosis (CE), but none seems promising for cyst viability assessment. Antigens with stage-specific diagnostic value have been described, but few studies with well-characterized antigens and human serum samples have been performed. Antigen B (AgB) proteoforms hold promise as markers of viability, due to their differential stage-related expression and immunoreactivity. Methods: Four AgB subunits (AgB1, AgB2, AgB3, AgB4) were synthesized and structurally characterized. Based on the preliminary evaluation of the subunits by western immunoblotting and enzyme-linked immunosorbent assay (ELISA), AgB1 and AgB2 were further tested in two ELISA setups and extensively validated on 422 human serum samples. Results: All subunits showed a high degree of spontaneous oligomerization. Interacting residues within oligomers were identified, showing that both the N-terminal and C-terminal of each subunit are involved in homo-oligomer contact interfaces. No hetero-oligomer was identified. AgB1 and AgB2 ELISAs revealed different sensitivities relative to cyst stage. Of note, besides high specificity (97.2%), AgB1 revealed a higher sensitivity for active-transitional cysts (100% for CE1, 77.8% for CE2, 81.5% for CE3a, and 86.3% for CE3b) than for inactive cysts (41.7% for CE4 and 11.1% for CE5) and postsurgical patients (44%). Interestingly, 19 of 20 patients with spontaneously inactive cysts and 6 of 9 treated with albendazole >5 years earlier were negative on the AgB1 assay. Conclusions: The structural characterization of subunits provides insights into the synthetic antigen conformation. The stage-related sensitivity of synthetic AgB1 holds promise as part of a multiantigen setting and deserves further longitudinal evaluation as marker of cyst viability.
KW - AgB
KW - Cyst viability
KW - Cystic echinococcosis
KW - Immunological characterization
KW - Serodiagnosis
KW - Structural
UR - http://www.scopus.com/inward/record.url?scp=85044656699&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85044656699&partnerID=8YFLogxK
U2 - 10.1093/cid/cix1006
DO - 10.1093/cid/cix1006
M3 - Article
VL - 66
SP - 1342
EP - 1351
JO - Clinical Infectious Diseases
JF - Clinical Infectious Diseases
SN - 1058-4838
IS - 9
ER -