An in silico approach to decipher immunogenic epitopes in Toxoplasma gondii GRA1 and GRA3

Abstract

Toxoplasma gondii (T. gondii) infection is a worldwide parasitic infection, causing serious threats to humans and livestock. Due to lack of a commercial vaccine, this study aimed at biochemical characterization and identification of immunogenic targets in GRA1 and GRA3 of T. gondii. A number of immunoinformatics web servers were used to predict antigenicity, allergenicity, solubility, physico-chemical properties, subcellular localization, post-translational modifications (PTMs), signal peptide and transmembrane domain, secondary and tertiary structure, along with B- and T-cell epitopes. Good antigenicity scores of 0.4815 (GRA1) and 0.5425 (GRA2) were predicted, without any allergenicity and Ig epitopes. Both proteins were soluble, hydrophilic and thermotolerable molecules. The length and molecular weight (MW) of GRA1 were 190 amino acids and 20.14 kDa, respectively, while the length of GRA3 was 222 residues with a MW of 24.24 kDa. Several antigenic epitopes were found in both protein sequences, some which were capable to induce IFN‐γ and/or IL-4 cytokines. In conclusion, we obtained comprehensive data on potential immunogenic epitopes through computer simulations. These findings serve as a basis for future Toxoplasma vaccine researches.