INTRACELLULAR HISTONE H2A IS RECOGNIZED BY CE AND OTHER PARASITOSIS IMMUNE SERA

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

Mar del Plata

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

Sociedad Argentina de Investigación Clínica

Echinococcus granulosus (Eg) causes cyst echinococcosis (CE), a worldwide distributed parasitic disease that affects livestock and humans. Our laboratory has developed the EGPE cell line from bovine Eg G1 protoscoleces (Echeverria et al, 2010) for studies of antiparasitic drugs and identification of relevant molecules in diagnosis and treatment of CE. This work aimed to identify and characterize proteins from Eg in the EGPE cells recognized by CE patients’ sera. Materials and methods: total proteins extract from EGPE cells 20 days grown was passed through a gel filtration column. Protein fractions were concentrated through a 3K cut‐off membrane concentrator. Reactive fractions to Western Blot were passed through affinity columns with CE or other parasitosis patient’s sera. Then isolated proteins were identified by proteomic in CEQUIBIEM (FCEyN, UBA). Proteins were modeled using Robetta platform (TrRosetta method) and validated by molecular dynamics simulations with software NAMD 2.14. Epitope prediction was performed with IEDB (linear epitope prediction and Discotope 2.0) and ABCpred. Results: We identified Eg’s Histone H2A (W6U0N3, 195 aa) recognized by sera from CE and others parasitosis patients. W6U0N3 has 81% identity in the first 58 aa with Fasciola hepatica’s histone H2A. Generated model was validated showing in 10-50 ns section of the trajectory an averaged potential energy resultant -168208 ± 198 kcal/ mol. This model presented two regions with different RMSD values for the trajectory taking the averaged structure as reference: for 1-14 aa region, 3.32 +/- 0.77 Å and for 14-195 aa region, 2.16 +/- 0.61 Å. Linear epitopes were predicted in 123-138, 138-153 and 170185 aa, meanwhile conformational epitopes were predicted in the 1-14 aa region. Conclusion: Intracellular Histone H2A from EGPE 118 cells is recognized by CE and others parasitosis patient’s sera, that could mean a marker for specific stages in the development of some parasitosis.