Enhanced Immune Response Against Echinococcus Granulosus Through a CTLA-4/B7 Affinity-Based Vaccine

<b>Background:</b> Echinococcosis is a zoonotic infectious disease that poses a significant threat to the health of individuals living in rural regions. While vaccination represents a potential strategy for disease prevention, there is currently no effective vaccine available for humans to prevent cystic echinococcosis (CE). This study aimed to design a novel multi-epitope vaccine (MEV) against Echinococcus granulosus for human use, employing immunoinformatics methods. <b>Methods:</b> We identified core epitopes from two key antigens, EgA31 and EgG1Y162, and integrated them into the immunoglobulin variable region of CTLA-4 (CTLA-4lgV) to create the <i>CVE31-162</i> vaccine construct. The secondary and tertiary structures of the <i>CVE31-162</i> were established using bioinformatics methods. The interaction between the <i>CVE31-162</i> and B7 molecules was assessed through molecular dynamics simulations. Finally, both in vitro and in vivo experiments were conducted to validate the effectiveness of the <i>CVE31-162</i> against the immunological effects of Echinococcus granulosus. <b>Results:</b> Bioinformatics analysis indicated that <i>CVE31-162</i> exhibits favorable antigenicity, stability, and non-allergenicity. Furthermore, <i>CVE31-162</i> demonstrated a stable three-dimensional structural model. Molecular docking (MD) and molecular dynamics simulations (MDS) revealed a strong binding affinity between <i>CVE31-162</i> and B7 molecules. Immune simulation results suggested that the vaccine elicits robust humoral and cell-mediated immune responses. Both in vitro and in vivo experiments demonstrated that immunized mice exhibited significantly elevated levels of antigen-specific antibodies and enhanced lymphocyte proliferation compared to the control group. <b>Conclusions:</b><i>CVE31-162</i>, which is based on the interaction between CTLA-4 and B7, represents a promising multi-epitope vaccine for Echinococcus granulosus.