A Multivalent Dengue Fusion Protein ΔcNS1-cEDIII-ΔnNS3 Confers Cross-Serotype Protection and Durable Immunity in...

Area of Science:

• * Virology and Immunology
• * Vaccine Development

Background:

• * Current dengue vaccines have limitations in serotype-specific efficacy and interference from pre-existing immunity.
• * Dengue virus (DENV) infection poses a significant global health challenge, necessitating improved vaccine strategies.

Purpose of the Study:

• * To develop and evaluate a novel multivalent fusion protein vaccine for broad protection against all four DENV serotypes.
• * To assess the immunogenicity and efficacy of the fusion protein vaccine in a murine model.

Main Methods:

• * Construction of a fusion protein vaccine comprising engineered dengue virus components: truncated nonstructural protein 1 (ΔcNS1), consensus envelope protein domain III (cEDIII), and truncated NS3 (ΔnNS3).
• * Immunization of mice with the fusion protein adjuvanted with Alum or Alum plus CpG oligodeoxynucleotides 1826 (CpG).
• * Evaluation of vaccine efficacy through assessment of viremia, bleeding time, antibody responses, T cell activity, and memory cell populations.

Main Results:

• * The fusion protein vaccine adjuvanted with Alum provided protection against all four DENV serotypes, reducing viremia and bleeding time.
• * Robust antibody and cellular immune responses, including enhanced CD8+ T cell activity and increased memory B and T cell populations, were observed.
• * Adjuvantation with CpG plus Alum further enhanced immunogenicity, leading to higher neutralizing activity and improved protection-relevant outcomes.
• * Two doses of the CpG plus Alum-adjuvanted vaccine conferred durable protection against a virulent DENV2 strain.

Conclusions:

• * The developed multivalent fusion protein vaccine is a promising subunit candidate for dengue prevention.
• * This novel vaccine demonstrates cross-serotype coverage and potential for long-term efficacy, addressing current vaccine limitations.