C67-09 A Multi Epitope Vaccine Based on Conserved Cd8+ T-cell Epitopes Against Human Metapneumovirus Infection

Abstract Background Human metapneumovirus (HMPV) is a major cause of acute respiratory tract infections in children, the elderly, and immunocompromised individuals, resulting in significant global morbidity and mortality. Despite the urgent clinical need, no licensed vaccine is currently available. The HMPV fusion (F) protein is a primary target for vaccine development due to its high conservation and role in viral entry. However, inducing robust cellular immunity, particularly CD8+ T cell responses, is considered crucial for effective viral clearance and protection. This study aimed to design a novel multi-epitope vaccine targeting conserved CD8+ T-cell epitopes to elicit broad and protective immunity against HMPV infection. Methods An immunoinformatic approach was employed to design a multi-epitope vaccine against Human Metapneumovirus (HMPV). Experimentally validated T-cell epitopes were obtained from the Immune Epitope Database (IEDB), and their antigenicity, toxicity, and allergenicity were assessed using ToxinPred and AllerTOP. Following the retrieval of HMPV genomic sequences from NCBI Virus, multiple sequence alignment (MAFFT) and phylogenetic analysis (IQ-TREE) were performed. Epitope conservation was rigorously evaluated via tBLASTn. Selected conserved epitopes were linked to construct the vaccine candidate, and its 3D structure was modeled with Robetta software. The recombinant protein was expressed in E. coli, purified, and formulated with an aluminum hydroxide adjuvant. BALB/c mice were immunized intramuscularly, and the immune response was evaluated by measuring serum antibody titers (ELISA) and examining lung tissue pathology (H&E staining). Results An immunoinformatic approach was employed to develop a multi-epitope vaccine against Human Metapneumovirus (HMPV). Nine highly conserved CD8+ T-cell epitopes were selected from the Immune Epitope Database (IEDB) and used to construct a vaccine protein comprising 149 amino acids. In silico analysis indicated the vaccine construct was stable, with an instability index of 32.29. For in vivo evaluation, BALB/c mice were immunized intramuscularly with the vaccine formulated with an aluminum hydroxide (alum) adjuvant. The vaccinated mice exhibited robust humoral immunity, with peak IgG antibody titers reaching 1:1,024,000. Histopathological examination of lung tissues demonstrated that vaccination alleviated HMPV-induced pulmonary damage compared to unvaccinated controls. Conclusion A novel multi-epitope vaccine was constructed using nine conserved CD8+ T-cell epitopes. When vaccine were adjuvanted with alum, elicited high IgG titers (up to 1:1,024,000) and reduced HMPV-induced lung injury in a murine model. This abstract is funded by: None