Thioredoxin Peroxidase: A Target for Vaccine Development and Serological Detection of Echinococcosis Introduction Human cystic echinococcosis (CE) is a chronic infection caused by the cestode Echinococcus granulosus. The robust humoral and cellular immune response elicited by this parasite. This study investigates the physicochemical and antigenic properties of the Thioredoxin peroxidase protein (XP_024356136.1) utilizing bioinformatics tools, aiming to evaluate its viability as a candidate for vaccine development and serological detection of Echinococcus granulosus across diverse host species. Methods The antigenicity, allergenicity, and toxicity of the TP protein were assessed using ANTIGENpro, AllerTop, and ToxinPred servers, respectively. The ProtParam server was employed to analyze the physicochemical characteristics of the protein. Additionally, linear Bcell and cytotoxic T lymphocyte (CTL) epitopes were predicted using the ABCpred webserver and the IEDB database, contributing to a comprehensive understanding of the protein's potential in immunological applications. Results The analysis demonstrated that the thioredoxin peroxidase (TP) protein is antigenic, with an ANTIGENpro score of 0.672609, and is classified as nonallergenic and non-toxic. Physicochemical characterization revealed a molecular weight of 21,405.51 Daltons and an estimated half-life of 30 hours in mammalian reticulocytes in vitro, over 20 hours in yeast in vivo, and more than 10 hours in Escherichia coli in vivo. The instability index was calculated to be 30.19, indicating favorable stability for vaccine formulation. Additionally, the aliphatic index of 85.39 classifies the protein as thermostable, while the theoretical isoelectric point (pI) was determined to be 5.79. The GRAVY index of -0.093 suggests a polar nature with significant water interaction, indicating high solubility. The protein comprises 24 negatively charged residues (aspartic acid and glutamic acid) and 21 positively charged residues (arginine and lysine), with a molecular formula of C954H1487N257O281S11 and a total atom count of 2,990. The QuerySol scaled solubility value was determined to be 0.455. Conclusions Our findings identified multiple linear Bcell and cytotoxic T lymphocyte (CTL) epitopes within the TP protein, all exhibiting high antigenicity, thereby highlighting their potential for application in vaccine development and serological detection of Echinococcus granulosus. 1.Khoshbakht, R., & Khosravi, A. (2020). Preliminary evaluation of recombinant EPC1 and TPx for serological diagnosis of animal cystic echinococcosis. Frontiers in Cellular and Infection Microbiology, 10, Article 177. https://doi.org/10.3389/fcimb.2020.00177 2.Tabrizi, M. M., & Shamsi, S. (2008). Thioredoxin peroxidase from Echinococcus granulosus: A candidate to extend the antigenic panel for the immunodiagnosis of human cystic echinococcosis. Journal of Parasitology Research, 2008, Article ID 5786949. https://doi.org/10.1155/2008/5786949 3.Mohammadi, A., & Fadaei, R. (2022). Interactions between innate immunity system and Echinococcus granulosus: Implications for vaccine development. Series of Medical Science, 3(1), 1-10. Retrieved from https://profdoc.um.ac.ir/articles/a/1092954.pdf
