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

by Kittipan Tharakhet, Eakachai Prompetchara, Chirayus Khawsang, Supichcha Saithong, Papatsara Kaewpang, Nongnaphat Yostrerat, Pachara Wangsoontorn, Jenjira Sontikun, Sawaros Tantratorn, Thidarat Khotprathum, Kieu Lam, James Heyes, Drew Weissman, Kiat Ruxrungtham, Chutitorn Ketloy

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.