Recombinant DENV type 1 Envelope Protein [His]

Background: Dengue is a global public health problem for which no drug or vaccine is available. Currently, there is increasing interest in developing non-replicating dengue vaccines based on a discrete antigenic domain of the major structural protein of dengue viruses (DENVs), known as envelope domain III (EDIII). The use of bio-nanoparticles consisting of recombinant viral structural polypeptides, better known as virus-like particles (VLPs), has emerged as a potential platform technology for vaccine development. This work explores the feasibility of developing nanoparticles based on E. coli-expressed recombinant Hepatitis B virus core antigen (HBcAg) designed to display EDIII moiety of DENV on the surface. Findings: We designed a synthetic gene construct encoding HBcAg containing an EDIII insert in its c/e1 loop. The fusion antigen HBcAg-EDIII-2 was expressed in E. coli, purified to near homogeneity using Ni+2 affinity chromatography and demonstrated to assemble into discrete 35-40 nm VLPs by electron microscopy. Competitive ELISA analyses showed that the EDIII-2 moieties of the VLPs are accessible to anti-EDIII-2-specific monoclonal and polyclonal antibodies, suggesting that they are surface-displayed. The VLPs were highly immunogenic eliciting high titer anti-EDIII-2 antibodies that were able to recognize, bind and neutralize infectious DENV based on ELISA, immunofluorescence and virus-neutralization assays. Conclusion: This work demonstrates that HBcAg-derived nanoparticles can serve as a useful platform for the display of DENV EDIII. The EDIII-displaying nanoparticles may have potential applications in diagnostics/vaccines for dengue.

Dengue fever remains as a serious infectious disease that can have horrible consequences, including death. Although it is not a new disease, there is no effective antiviral drug available to treat this disease. In this study, fragment-based drug design and molecular docking approach have been done to generate the potential drug candidates for inhibiting beta-OG pocket binder of the envelope protein responsible for mediating DENV entry into the host cell. About 190,084 natural product compounds were obtained from ZINC15 database. The rules of three and pharmacological test were employed against the natural product compounds, resulting 1,610 favorable fragments. These fragments were docked into the polar and nonpolar regions of beta-OG pocket binder cavity, respectively. The potential fragments, which bound to each region, were linked to generate 6,487 ligands. The rules of five and pharmacological test against the ligands have been done to discard the ligands with the undesired molecular properties. The inhibition activity of 2,950 ligands was evaluated by employing rigid and flexible molecular docking simulation. AX1312, AZ0830, and AZ0492 show a promising potential as the drug leading candidate for treating dengue fever as they have a better binding free energy and molecular interaction with DENV envelope protein compared to the standard compound, n-octyl-beta-D-glucoside. Further in vitro and in vivo analysis are required to validate their inhibition activity against DENV envelope protein under actual biological condition.