Bioinformatics-Driven Design of Fusion Recombinant Protein (EgFABP1-EgTeg) for Enhanced Immunodiagnosis of Hydatid Cysts

<h4>Background</h4>Hydatid cyst disease is caused by the parasite Echinococcus and poses significant health concerns worldwide. Due to the lack of early symptoms and limited diagnostic tools, researchers aim to design a more specific and sensitive antigen. The study focuses on developing a recombinant multi-epitope antigen using two parasite proteins (EgTeg and EgFABP1) and the IH4 nanobody.<h4>Methods</h4>Protein sequences were analyzed and validated using bioinformatics tools, and B-cell epitopes were identified. The resulting antigen, confirmed by UniProt, is 266 amino acids long.<h4>Results</h4>The multi-epitope antigen lacks a signal peptide and contains 46 phosphorylation sites associated with serine and tyrosine. Structural predictions showed both alpha helices and beta sheets in the secondary structure, with a spherical tertiary structure. Both linear and discontinuous epitopes were predicted, indicating regions with potential to stimulate immune responses. The antigen's physicochemical properties-molecular weight, isoelectric point stability index, and hydrophilicity-indicate that it is stable and suitable for diagnostic use.<h4>Conclusions</h4>The study introduces the EgFABP1-EgTeg-IH4 recombinant protein as a promising candidate for diagnosing HC disease. By integrating multiple antigenic regions and the IH4 nanobody, this approach significantly improves diagnostic specificity and sensitivity, offering the potential for more accurate, earlier detection.