Plant-Produced Anti-Enterovirus 71 (EV71) Monoclonal Antibody Efficiently Protects Mice Against EV71 Infection

Enterovirus 71 (EV71) is the main causative agent of severe hand-foot-mouth disease. EV71 affects countries mainly in the Asia-Pacific region, which makes it unattractive for pharmaceutical companies to develop drugs or vaccine to combat EV71 infection. However, development of these drugs and vaccines is vital to protect younger generations. This study aims to develop a specific monoclonal antibody (mAb) to EV71 using a plant platform, which is a cost-effective and scalable production technology. A previous report showed that D5, a murine anti-EV71 mAb, binds to VP1 protein of EV71, potently neutralizes EV71 in vitro, and effectively protects mice against EV71 infection. Herein, plant-produced chimeric D5 (cD5) mAb, variable regions of murine D5 antibody linked with constant regions of human IgG1, was transiently expressed in Nicotiana benthamiana using geminiviral vectors. The antibody was expressed at high levels within six days of infiltration. Plant-produced cD5 retained its in vitro high-affinity binding and neutralizing activity against EV71. Furthermore, a single dose (10 µg/g body weight) of plant-produced cD5 mAb offered 100% protection against infection in mice after a lethal EV71 challenge. Therefore, our results showed that plant-produced anti-EV71 mAb is an effective, safe, and affordable therapeutic option against EV71 infection.