Coxsackievirus A16-like particles produced in Pichia pastoris elicit high-titer neutralizing antibodies and confer protection against lethal viral challenge in mice

Abstract

Coxsackievirus A16 (CA16) is a major causative agent of hand, foot and mouse disease (HFMD) which has been affecting millions of young children annually in the Asia–Pacific region over the last seven years. However, no commercial CA16 vaccines are currently available. In the present study, we investigated the expression of virus-like particles (VLPs) of CA16 in Pichia pastoris yeast and their immunogenicity and protective efficacy in mice. We found that CA16-VLPs could be produced at relatively high levels in P. pastoris yeast transformed with a construct co-expressing the P1 and 3CD proteins of CA16. Mice immunized with the yeast-derived CA16-VLPs produced high-titer serum antibodies with potent neutralization effect specifically on CA16. More importantly, passive immunization with the yeast-derived VLPs fully protected neonatal mice against CA16 lethal challenge in both antisera transfer and maternal immunization experiments. Collectively, our results demonstrate that P. pastoris-derived CA16-VLPs represent a promising CA16 vaccine candidate with proven preclinical efficacy and desirable traits for manufacturing at industrial scale.