Toxoplasma gondii microneme protein 3 (TgMIC3): Computational probing for improved vaccine design

Abstract

Background: Microneme protein 3 (MIC3) is a robust adhesion molecule in Toxoplasma gondii (T. gondii) that is expressed in all infection stages. This study aimed to predict different useful features of the T. gondii-MIC3 protein to confirm its suitability for inclusion in vaccine formulations.

Methods: Several bioinformatics online servers and tools were recruited to predict physicochemical characteristics, allergenicity, antigenicity, solubility, post-translational modification (PTMs) regions, subcellular localization, transmembrane domains, signal peptides, tertiary and secondary structures, potential T- and B-lymphocyte epitopes, and virtual simulation of immune responses in TgMIC3.

Results: Based on the analysis, 75 post-translational modification sites were recognized in TgMIC3. The GOR IV, SOPMA, and NetSurfP-3.0 online servers revealed that the secondary structure of the MIC3 protein frequently consists of random coils and extended strands. Additionally, several potential T- and B-lymphocyte epitopes were observed on TgMIC3. The structure assessment tool revealed that 82.91% and 98.60% of the amino acid residues were incorporated in the favored areas in the initial and refined models, respectively. The findings of the allergenicity and antigenicity assessments indicated that the MIC3 antigen seemed to be a non-allergen with an immunogenic nature. In silico immune simulation by the C-ImmSim web-based server confirmed that TgMIC3 is capable of provoking both humoral and cell-mediated immune responses after three injections.

Conclusion: This research project provides baseline data for subsequent studies on the role of the TgMIC3 protein in the development of vaccine candidates for acute and latent toxoplasmosis.