Polymeric nanoengineered HBsAg DNA vaccine designed in combination with β‑glucan

Abstract Antigen-specific immune responses following DNA vaccination are hard to achieve, owing to the difficulty to mediate efficient gene delivery. This study proposed the use of PDMAEMA:PβAE/DNA polyplexes (Pol) as the vehicle of a pDNA vaccine encoding the hepatitis B surface antigen (HBsAg), with these Pol designed in combination with a soluble (Glu) or a particulate (GPs) form of β‑glucan. β‑Glucans are recognized adjuvants that activate immune cells, a good strategy to improve transfection efficiency and vaccine efficacy. Results showed that Pol produced at a 19:1 polymer:DNA (+/−) charge ratio were positively charged (+41 mV), had a mean size of 180 nm and presented high stability under different storage conditions. These polyplexes resulted in enhanced transfection activity than the positive control, showing even higher luciferase gene expression in the presence of GPs (COS-7 and RAW 264.7 cell lines). Additionally, no alterations in hemolysis and plasma coagulation time of human blood were found in the non-cytotoxic working range. Mice vaccination studies (pCMV-S), resulted in a seroconversion rate of 40%, regardless of the additional β‑glucan adjuvants. This work showed the potential of this nanosystem together with GPs to enhance in vitro transfection capacity and to be further studied as a DNA vaccination platform.