Humoral Immune Response in a Mouse Model Induced With Dengue Virus-like Particles Serotypes 1 and 4 Produced in Silkworm Larvae

Abstract

Dengue is an arboviral disease, which threatens almost half the global population, and has emerged as the most significant of current global public health challenges. In this study, we prepared dengue virus-like particles (DENV-LPs) consisting of Capsid-Premembrane-Envelope (CprM/E) and Premembrane-Envelope (prM/E) polypeptides from serotype 1 and 4, which were expressed in the silkworms using Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid. 1CprME, 1prME, 4CprME, and 4prME expressed proteins in hemolymph and molecular weight of the purified proteins were 55 kDa, respectively. The purified polypeptides formed spherical Dengue virus-like particles (DENV-LPs) with approximately 30–55 nm in diameter. The immunoelectron microscopy (IEM) images revealed antigens to the surface of a lipid bilayer of DENV-LPs. The heparin-binding assay shows a positive relationship between absorbance and the quantity of E protein domain III (EDIII), which was supported by the isothermal titration calorimetry assay, showing a moderate binding affinity between heparin and DENV-LP. The high correlation between patient sera and DENV-LP reactivities revealed that these DENV-LPs shared similar epitopes with the natural dengue virus. IgG elicitation studies in mice have demonstrated that DENV-LP/CPrMEs elicits a stronger immune response than DENV-LP/prMEs, which lends credence to this claim.