Immunogenicity of a candidate DNA vaccine based on the prM/E genes of a dengue type 2 virus Cosmopolitan genotype

抄録

The development of a dengue vaccine is a major priority. Several researchers are using Asian 1 and Asian 2 genotypes as vaccine candidates to develop a vaccine for dengue type 2 virus (DENV-2). However, in this study, we constructed a recombinant plasmid-based prM-E gene from the DENV-2 Cosmopolitan genotype as a dengue DNA vaccine candidate. The protein expression levels of recombinant plasmids in CHO cell lines were analyzed using an enzyme-linked immunosorbent assay, western blotting, and sucrose gradients. After immunizing ddY mice three times, DNA vaccine doses of 25 and 100 µg induced humoral immune responses. There was no difference in the neutralizing antibody titer (focus reduction neutralization test 50%) of mice immunized with 25 and 100 µg DNA vaccine doses. A challenge test using 3 × 10⁵ FFU DENV-2 showed that immunized mice could raise anamnestic neutralizing antibody responses at day 4 and 8 post-challenge. An immunogenicity test with BALB/c mice showed that their antibody neutralization titers were lower than those of ddY mice. In addition, the antibodies produced after immunization and challenge test could also neutralize DENV-2 Asian 2 genotype (NGC strain). Thus, the DENV-2 Cosmopolitan genotype may be a DENV-2 vaccine candidate.