Background Immunoinformatics approaches have facilitated the prediction of B and T-cell epitopes for the development of vaccines against Toxoplasma gondii ( T. gondii ) infection. Objectives In this study, immunoinformatic approaches and in silico protein structure prediction tools were employed to investigate the various characteristics of T. gondii rhoptry protein 5 (TgROP5), a virulence-associated protein of this apicomplexan parasite. Methods The evaluated properties included physicochemical characteristics, solubility, allergenicity, antigenicity, post-translational modification (PTM) sites, secondary and tertiary structures, subcellular localization, signal peptides, three-dimensional model refinement and validation, prediction of potential B- and T-lymphocyte epitopes, and virtual immune simulation. Results TgROP5 consists of 549 amino acids and has an estimated molecular weight of 61,102.03 Da. The hydropathicity of TgROP5, determined via the grand average of hydropathicity (GRAVY) index, was −0.233, whereas the aliphatic index was calculated to be 87.96. A total of 60 PTM sites were identified in TgROP5, including 1 acetylation site, 48 phosphorylation sites, and 11 N-glycosylation sites. The findings of the GORIV, SOPMA, and NetSurfP-3.0 servers revealed that random coils were the predominant secondary structural elements. Moreover, structure assessment demonstrated that 89.03% and 97.62% of residues were located in favored regions for the initial and refined models, respectively, indicating improvement of the three-dimensional model Allergenicity prediction tools suggested that TgROP5 is likely to be a non-allergen. TgROP5 was further analyzed using the SVMTriP, ABCpred, BcePred, ElliPro, and Immune Epitope Database (IEDB) web servers, which identified multiple potential B- and T-cell epitopes. In silico immune simulation performed using the C-ImmSim web server demonstrated that TgROP5 could induce both humoral and cell-mediated immune responses following three antigen injections. Conclusions Further experimental validation is required to provide a more comprehensive understanding of these findings and to evaluate the immunological relevance of the predicted epitopes through in vitro and in vivo studies.
Foroutan et al. (Fri,) studied this question.