Optimized multi-epitope neoantigen human cytomegalovirus vaccine based on adenovirus vectors elicits potent antiviral immunity.

Introduction: Human cytomegalovirus (HCMV) induces severe morbidity and mortality in neonates, organ transplant recipients, and immunocompromised individuals. Currently, there is no licensed vaccine for HCMV. Given its ability to elicit a robust and enduring CD8 T cell response, we designed a recombinant adenovirus vaccine, referred to as the rAdMev vaccine, using bioinformatics methods based on human cytomegalovirus multi-antigen epitopes. Methods: Five proteins of HCMV (pp150, pp65, gB, gH, IE1) were analyzed using bioinformatics tools, and 58 T cell epitopes, 66 Th cell epitopes, and 15 B cell epitopes were screened out. The immunogenicity of the overlapping candidate peptides was initially tested Results: The developed vaccine demonstrates favorable characteristics in terms of major histocompatibility complex affinity, immunogenicity, and population coverage. Primary immunization of mice with the rAdMev vaccine induces a potent innate immune response, characterized by highly activated dendritic cell subsets and the polarization of macrophages towards the M1 phenotype. Heterologous vaccination fosters the generation of robust polyfunctional (IFN-γ, TNF, IL-2, Granzyme B, Perforin) CD8 T cell responses, leading to the establishment of persistent effector memory T cells. Furthermore, we observed that heterologous vaccination activates fatty acid β-oxidation through the PPAR signaling pathway, enhancing mitochondrial biogenesis and promoting CD8 T cell memory formation Conclusions: We have developed a novel multi-epitope recombinant adenovirus vaccine that can elicit long-lasting antiviral cellular immunity, providing new insights into the development of vaccines against HCMV.