A plasmid encoding parts of the dengue virus E and NS1 proteins induces an immune response in a mouse model

A DENV-2 plasmid named pEII*EIII/NS1*, containing sequences encoding portions of the envelope protein that are potentially involved in the induction of neutralizing antibodies and a portion of the NS1 sequence that is involved in protection, is reported in this work. The synthesized subunit protein was recognized by human sera from infected patients and had the predicted size. The immunogenicity of this construct was evaluated using a mouse model in a prime-boost vaccination approach. The priming was performed using the plasmid pEII*EIII/NS1*, followed by a boost with recombinant full-length GST-E and GST-NS1 fusion proteins. The mice showed specific antibody responses to the E and NS1 proteins, as detected by ELISA, compared to the response of animals vaccinated with the parental plasmid. Interestingly, some animals had neutralizing antibodies. These results show that EII*, EIII and NS1* sequences could be considered for the design of a recombinant subunit vaccine against dengue disease.