反向疫苗学与免疫信息学方法在新型多表位mRNA疫苗研发中的应用——以对抗弓形虫（Toxoplasma gondii）为例

《Human Immunology》：Reverse vaccinology and immunoinformatics Approaches Driven designing of a Novel Multi-Epitope mRNA vaccine against Toxoplasma gondii

本研究利用反向疫苗学和免疫信息学，基于MIC1、MIC3、ROP29和SAG1蛋白设计了一款mRNA疫苗。该疫苗epitopes全球覆盖率100%，生物物理性质稳定，与TLR-2和TLR-4结合亲和力高，免疫模拟显示能有效激活B和T细胞，为未来开发抗弓形虫疫苗提供了理论依据。

　　
Toxoplasmosis is a widespread zoonotic infection caused by the apicomplexan parasite *Toxoplasma gondii*. Despite its global prevalence, therapeutic options remain limited, with chemotherapy suffering from side effects, teratogenicity, and inability to eliminate tissue cysts. This study introduces a novel mRNA vaccine targeting MIC1, MIC3, ROP29, and SAG1 proteins, leveraging reverse vaccinology and immunoinformatics. These proteins are critical for parasite attachment, invasion, and immune evasion, making them ideal candidates for vaccine development.

The research begins by isolating high-quality protein sequences from the UniProt database for the four selected antigens. Multi-sequence alignment and phylogenetic analysis confirm the evolutionary stability and diversity of these proteins across different strains. Signal peptide screening ensures the selected epitopes are properly processed and displayed on the parasite surface, enhancing their immunogenic potential.

A key innovation lies in combining multiple antigens into a single mRNA vaccine construct. This approach addresses the limitations of previous studies that focused on individual proteins or limited combinations. The chosen antigens—MIC1 and MIC3 for their role in host cell recognition, ROP29 for persistent infection regulation, and SAG1 for surface exposure—form a comprehensive target profile. Computational tools predict these epitopes to cover 100% global HLA alleles, ensuring broad population applicability.

Structural optimization is critical for vaccine efficacy. The refined vaccine design achieves a Ramachandran score of 80.9%, indicating well-structured domains, while a Z-score of -7.55 suggests high stability under physiological conditions. Molecular docking simulations reveal strong binding affinity for TLR-2 and TLR-4 receptors, with energy scores as low as -1008.6 kJ/mol, signaling favorable interactions. These biophysical properties support the vaccine’s ability to survive in the human body and trigger effective immune responses.

Immune simulation data highlight dual activation of B and T cells, a hallmark of robust adaptive immunity. The vaccine’s mRNA format aligns with modern nucleic acid vaccine strategies, avoiding genomic integration risks and enabling rapid modification. This approach mirrors the success of COVID-19 mRNA vaccines, providing a scalable and safe platform for toxoplasmosis prevention.

Notably, the study emphasizes the necessity of bridging computational predictions with experimental validation. While in-silico modeling confirms promising stability and receptor binding, in-vivo testing remains essential to assess efficacy in immunocompromised populations and verify long-term safety. The absence of prior mRNA vaccine research for *T. gondii* positions this work as a foundational step in parasite vaccine development.

Limitations include potential discrepancies between computational models and biological systems, particularly regarding antigen processing and immune memory. Additionally, structural stability predictions under varying pH and temperature conditions require further exploration. The authors acknowledge these constraints but stress the strategic value of integrating reverse vaccinology with contemporary mRNA technologies.

The broader implications extend beyond human health. Since *T. gondii* infections in livestock cause significant economic losses andzoonotic transmission risks, this vaccine could address both public health and agricultural challenges. Its multi-antigen design also offers a template for combating other apicomplexan diseases, such as coccidiosis in poultry.

In summary, this study advances vaccine development for toxoplasmosis through innovative integration of reverse vaccinology and mRNA technology. The comprehensive antigen selection, rigorous structural validation, and promising immune induction signals provide a credible pathway toward future clinical applications. However, the transition from computational proof-of-concept to real-world efficacy demands collaborative efforts between bioinformatics and virology experts, ensuring both scientific rigor and practical relevance in parasite vaccine design.