HeterologousPrime-Boost immunizationwithAdenoviral vector and recombinant subunit vaccines strategies against dengue virus type2.

Dengue virus (DENV) remains a significant public health threat in tropical and subtropical regions, with effective antiviral treatments and vaccines still not fully established despite extensive research. A critical aspect of vaccine development for DENV involves selecting proteins from both structural and non-structural regions of the virus to activate humoral and cellular immune responses effectively. In this study, we developed a novel vaccine for dengue virus serotype 2 (DENV2) using a heterologous Prime-Boost strategy that combines an adenoviral vector (Ad) with subunit vaccines. The vaccine design included non-structural protein 1 (NS1), envelope protein domain III (EDIII), and the bc-loop of envelope domain II (EDII) as conserved epitopes. These antigens were fused into a single construct P1 and inserted into the pAdTrack-CMV vector to produce a recombinant adenovirus (rAd5-P1) via homologous recombination in E. coli. The examination of the immune response indicated that strong humoral and cellular immunity was generated in various groups of mice. Additionally, the group receiving a heterologous regimen of recombinant adenovirus and protein showed a superior balance of humoral and cellular immunity in terms of IgG2a/IgG1 and INF-γ /IL-4 ratios. These findings validate the vaccine design's ability to utilize both structural and non-structural proteins to generate strong immune responses on two platforms. The promising results from the heterologous regimen highlight its potential as an effective DENV2 vaccine candidate. This research offers significant insights into developing safe and effective DEN vaccines, contributing to efforts to control DENV infections.