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

MAGLIOCO A; AGUERO F; VALACCO P; JUAREZ VALDEZ A; PAULINO M; FUCHS A

Congreso; REUNIÓN DE SOCIEDADES DE BIOCIENCIAS 2021; 2021

Cystic echinococcosis (CE) is a zoonotic disease produced byEchinococcus granulosus worldwide distributed. The discovery ofnew antigens would improve the CE diagnosis. EGPE is a cell lineobtained from bovine E granulosus protoscoleces G1 in our laboratory(Echeverria et al, 2010). We have previously demonstratedthat EGPE cells are a good source of antigens for CE diagnosis(Maglioco et al, 2019). The aim of this work was to identify the EGPEproteins recognized by CE patients? sera. Materials and Methods:EGPE cells were grown in agarose 2% (20000 cells / well) for 5days. The supernatant of cell colonies was passed through G-proteinaffinity columns performed with sera from patients with 1) CE or2) other parasitoses. Eluted proteins were concentrated (3K cut‐offmembrane concentrator), run in 15% SDS-PAGE, stained, and isolatedfor protein identification in CEQUIBIEM (FCEyN, UBA). Molecularmodeling of the protein was performed using TrRosetta methodfrom Robetta platform. Validation of the model was performedby molecular dynamics using NAMD 2.14. Epitope prediction wasperformed using IEDB (linear epitope prediction and Discotope 2.0)and ABCpred. All protocols were approved by the Ethics Committeeof the ?UAI?. Results: The Histone H2A (W6UJM4), a proteinof 189 amino acids (aa), was identified among other proteins onlyin eluates from CE column. The model was validated. In the 10-50 ns section of the trajectory, the averaged potential energy was-165510 +/- 190 kcal/mol. The protein has two regions with differentdynamic behavior: the RMSD for the trajectory taking the averagedstructure as reference was 2.76 +/- 0.65 Å for 1-160 aa region and4.59 +/- 1.04 Å for 160-189 aa region. The linear and conformationalepitopes were predicted in 27-42, 55-70, 92-107, 142-157 aa and54-75, 100-104, 169-189 aa, respectively. Conclusions: The histoneH2A is a candidate for serological detection of CE. Further studiesare required to prove its diagnostic accuracy.