Phage vaccines displaying YGKDVKDLFDYAQE epitope induce protection against systemic candidiasis in mouse model.

Candida albicans is a common commensal and opportunistic fungal pathogen in human, which poses threat to human health, especially in immunocompromised patients. Unfortunately, few effective prophylactic and therapeutic strategies were applied to clinic practice. Recently, the peptide YGKDVKDLFDYAQE from Fructose-bisphosphate aldolase 1 (Fba1), as a vaccine, was reported to induce protection effects against systemic candidiasis. Here, we displayed this epitope peptide on the coat proteins (pIII or pVIII) of filamentous phage, and investigated their protective effects against C. albicans infections. Mice were immunized with recombinant phages (designated as phage-3F and phage-8F) or protein (rFba1), then challenged with C. albicans yeast cells via lateral tail vein. Results demonstrated that the recombinant phages as well as rFba1 apparently induced humoral and cellular immune responses, reduced fungal burden and relieved kidney damage in infected mice and significantly improved their survival rates. Briefly, all these findings indicated that the recombinant phages displaying the epitope YGKDVKDLFDYAQE have the potential to be developed into a new vaccine against C. albicans infections.