Protective immunity to DENV2 after immunization with a recombinant NS1 protein using a genetically detoxified heat-labile toxin as an adjuvant

► A subunit vaccine with DENV2 NS1 as antigen was proposed. ► LTG33D was used as an adjuvant for the first time in a DENV vaccine formulation. ► Antibodies with high affinity to DENV2 NS1 were generated. ► The immune response conferred protection of 50% under lethal challenge. ► The proposed vaccine did not elicited side effects in immunized mice.