Enterovirus 71 (EV71) is a primary causal agent of hand, foot, and mouth disease (HFMD) in children. Even though 3 inactivated virus-based HFMD vaccines are approved in China, other techniques have been tried to generate an effective and safer vaccine that is simpler to manufacture. Among these is an EV71 vaccine based on virus-like particles (VLPs) under active development. An effective approach for producing EV71-VLPs using recombinant technology is required for this purpose. The study presents the creation and expression of the EV71 P1 and 3C genes in Pichia pastoris for the production of VLP-based EV71 vaccine antigen with a high yield and simple manufacturing process.

EV71-VLPs were successfully produced in the Pichia pastoris system using codon-optimized P1 and 3C genes, and the expression level reached 270 mg/L. Biochemical and biophysical investigations revealed that the EV71-VLPs were made up of processed VP0, VP1, and VP3 in the form of 35nm spherical particles. For vaccine development, the immune response as a function of EV71-VLPs and adjuvant dosage ratio was studied. Immunization with 1–5 g/dose EV71-VLPs and 225 g/dose adjuvant generated strong neutralising antibody responses and provided efficient protection against fatal challenge in both maternally transmitted antibody and passive transfer protection mouse models. As a result, the yeast-produced EV71-VLPs antigen represents a good option for the development of an HFMD vaccine.

Reference: https://www.tandfonline.com/doi/full/10.1080/21645515.2019.1649554