A secretion-deficient DENV1 DNA vaccine induces durable immunity and confers protection against DENV2

Antibody-dependent enhancement (ADE) remains a major obstacle to dengue virus (DENV) vaccine development and continues to make safe, broadly protective vaccination a global health priority (Aggarwal et al., 2024; Halstead et al., 2014; Martinez et al., 2021; Paz-Bailey et al., 2024; Shepard et al., 2016). This study generated two DNA-based DENV vaccine constructs encoding premembrane (prM) and envelope (E) proteins: a secretion-deficient mutant (DNSP) and a full-length wild-type (WT) prM-E protein. Both vaccines elicited cell-mediated immune responses and protected mice against lethal DENV1 challenge. DNSP immunization induced minimal anti-prM-E antibody production but conferred durable protection, as evidenced by sustained T cell responses and challenge experiments performed one year after vaccination. In vitro DENV infection assays further showed that DNSP reduced K562 cell infection across all four DENV serotypes. In vivo DENV2 challenge also demonstrated that DNSP conferred effective protection against DENV2 infection. These findings identify secretion-deficient prM-E DNA vaccination as a promising strategy for strengthening cell-mediated antiviral immunity while limiting antibody induction. DNSP may therefore serve as a booster immunogen with potential to reduce ADE-associated risk during DENV vaccination.