Recombinant Fusion Protein Vaccine Containing Clostridioides difficile FliC and FliD Protects Mice against C. difficile Infection

Bacterial flagella are involved in infection through their roles in host cell adhesion, cell invasion, auto-agglutination, colonization, the formation of biofilms, and the regulation and secretion of nonflagellar bacterial proteins that are involved in the virulence process. In this study, we constructed a fusion protein vaccine (FliCD) containing the Clostridioides difficile flagellar proteins FliC and FliD. The immunization of mice with FliCD induced potent IgG and IgA antibody responses against FliCD, protected mice against C. difficile infection (CDI), and decreased the C. difficile spore and toxin levels in the feces after infection. Additionally, the anti-FliCD serum inhibited the binding of C. difficile vegetative cells to HCT8 cells. These results suggest that FliCD may represent an effective vaccine candidate against CDI. Bacterial flagella are involved in infection through their roles in host cell adhesion, cell invasion, auto-agglutination, colonization, the formation of biofilms, and the regulation and secretion of nonflagellar bacterial proteins that are involved in the virulence process. In this study, we constructed a fusion protein vaccine (FliCD) containing the Clostridioides difficile flagellar proteins FliC and FliD.

Automated summary

Bacterial flagella play crucial roles in infection by mediating host cell adhesion, invasion, auto-agglutination, colonization, biofilm formation, and the regulation and secretion of nonflagellar bacterial proteins associated with virulence. In this study, a fusion protein vaccine (FliCD) containing Clostridioides difficile flagellar proteins FliC and FliD was constructed. Immunization with FliCD induced robust IgG and IgA antibody responses, provided protection against C. difficile infection, and reduced C. difficile spore and toxin levels in the feces. Furthermore, the anti-FliCD serum inhibited the binding of C. difficile vegetative cells to HCT8 cells. These findings suggest that FliCD may serve as an effective vaccine candidate against CDI.