HISTONE H2A (W6UJM4) IS RECOGNIZED BY SERA FROM PATIENTS WITH CYSTIC ECHINOCOCCOSIS IN EGPE CELLS COLONIES SUPERNATANT

MAGLIOCO, ANDREA; AGUERO F; VALACCO MARIA PIA,; JUAREZ VALDEZ; PAULINO, MARGOT; FUCHS, ALICIA G

Mar del Plata

Congreso; Reunion conjunta anual SAIC, SAI, AAFE, NANOMED-A 2021 Buenos Aires, Argentina, noviembre 2021; 2021

Sociedad Argentina de Investigación Clínica

Cystic echinococcosis (CE) is a zoonotic disease produced by Echinococcus granulosus worldwide distributed. The discovery of new antigens would improve the CE diagnosis. EGPE is a cell line obtained from bovine E granulosus protoscoleces G1 in our laboratory (Echeverria et al, 2010). We have previously demonstrated that EGPE cells are a good source of antigens for CE diagnosis (Maglioco et al, 2019). The aim of this work was to identify the EGPE proteins recognized by CE patients’ sera. Materials and Methods: EGPE cells were grown in agarose 2% (20000 cells / well) for 5 days. The supernatant of cell colonies was passed through G-protein affinity columns performed with sera from patients with 1) CE or 2) other parasitoses. Eluted proteins were concentrated (3K cut‐off membrane concentrator), run in 15% SDS-PAGE, stained, and isolated for protein identification in CEQUIBIEM (FCEyN, UBA). Molecular modeling of the protein was performed using TrRosetta method from Robetta platform. Validation of the model was performed by molecular dynamics using NAMD 2.14. Epitope prediction was performed using IEDB (linear epitope prediction and Discotope 2.0) and ABCpred. All protocols were approved by the Ethics Committee of the “UAI”. Results: The Histone H2A (W6UJM4), a protein of 189 amino acids (aa), was identified among other proteins only in eluates from CE column. The model was validated. In the 1050 ns section of the trajectory, the averaged potential energy was -165510 +/- 190 kcal/mol. The protein has two regions with different dynamic behavior: the RMSD for the trajectory taking the averaged structure as reference was 2.76 +/- 0.65 Å for 1-160 aa region and 4.59 +/- 1.04 Å for 160-189 aa region. The linear and conformational epitopes were predicted in 27-42, 55-70, 92-107, 142-157 aa and 54-75, 100-104, 169-189 aa, respectively. Conclusions: The histone H2A is a candidate for serological detection of CE. Further studies are required to prove its diagnostic accuracy.