DEAR EDITOR,The development of an effective tetravalent vaccine against dengue viruses (DENVs) has become a world priority.We previously showed that four monovalent dengue DNA vaccines expressing premembrane (prM) and envelope (E) proteins displayed effective protection against corresponding challenges in mice.Thus,to elucidate the overall immunity and persistence of the tetravalent formulation (TetraME),we evaluated the humoral and cellular immune responses as well as the long-term protection in the current study.TetraME-immunized mice displayed increased production of Th1/Th2-typed cytokines upon stimulation with heterologous DENV antigens.Moreover,high levels of tetravalent DENV antibodies and sterilized immunity were detected long-term (30 weeks after immunization).These findings provide feasible validation for the potential utility of this vaccine formulation.