Cross-serotype immunity elicited by a consensus dengue NS1 mRNA vaccine in mice

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 additional protection and reduced disease severity, supporting its inclusion in vaccine design. In this study, we designed a consensus NS1 (cNS1) antigen by integrating sequence elements from all four DENV serotypes (78-89% amino acid identity) to enhance cross-serotype antigenic coverage. 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 broadly reactive NS1-specific IgG responses that recognized NS1 proteins from all four serotypes. In addition, the vaccine elicited interferon-γ (IFN-γ)-producing T cell responses against peptide pools derived from multiple DENV serotypes, indicating the activation of cross-reactive cellular immunity. While broad immune recognition was achieved, this was accompanied by lower serotype-specific response magnitudes as a trade-off. In conclusion, the cNS1 mRNA vaccine induces cross-serotype humoral and cellular immune responses in mice, highlighting the potential of consensus antigen design to broaden immune recognition of DENV NS1. These findings support the further development of NS1-based immunogens as complementary components of next-generation dengue vaccines aimed at achieving broad and effective protection.