Design and immunogenicity study of a consensus dengue ns1 mRNA vaccine in mice

Abstract

Dengue virus (DENV) remains a major global health burden, with four antigenically distinct serotypes (DENV-1–4) posing a significant challenge for vaccine development. Dengue non-structural protein 1 (NS1) has been associated with protective immune responses and reduced disease severity, supporting its inclusion in vaccine design. In this study, a consensus NS1 (cNS1) antigen was designed using a two-step consensus strategy that integrated sequence information from all four DENV serotypes. Sequence analysis demonstrated that the cNS1 construct shared 78–89% amino acid identity with reference NS1 proteins and retained multiple reported functional motifs, protective antibody-associated regions, and T-cell epitope-rich regions. The cNS1 sequence was encoded as a nucleoside-modified mRNA and formulated in lipid nanoparticles (mRNA–LNPs). Immunization of BALB/c mice with a low dose (0.2 µg) of cNS1 mRNA–LNP induced cross-reactive NS1-specific IgG responses that recognized NS1 proteins from all four DENV serotypes. In addition, the vaccine elicited interferon-γ (IFN-γ)-producing T-cell responses against peptide pools derived from all four DENV serotypes, indicating activation of cross-reactive cellular immunity. Although immune responses were detected against all serotypes, response magnitudes differed among serotypes and were generally lower than homologous responses induced by serotype-specific NS1 vaccines. In conclusion, the cNS1 mRNA vaccine induced cross-serotype humoral and cellular immune responses while preserving key structural and immunologically relevant NS1 regions. These findings demonstrate the feasibility of consensus-based NS1 antigen design for broad serotype coverage and support the further development of NS1-based immunogens as complementary components of next-generation dengue vaccines.