Development and characterization of a plant-derived rotavirus-like particle vaccine

Background: Virus-like particles (VLPs) are unable to replicate in the recipient but stimulate the immune system through recognition of repetitive subunits. Parenterally delivered rotavirus-VLP (Ro-VLP) vaccine could have the potential to overcome the weaknesses of licensed oral live-attenuated rotavirus vaccines, namely, low efficacy in low-income and high mortality settings and a potential risk of intussusception. Methods: A monovalent Ro-VLP composed of viral protein (VP) 7, VP6 and VP2 of G1 genotype specificity was produced in Nicotiana benthamiana using Agrobacterium tumefaciens infiltration-based transient recombinant expression system. Plants expressing recombinant G1 Ro-VLP were harvested, then the resultant biomass was processed through a series of clarification and purification steps including standard extraction, filtration, ultrafiltration and chromatography. The purified G1 Ro-VLP was subsequently examined for its immunogenicity and toxicological profile using animal models. Results: G1 Ro-VLP had a purity of >= 90% and was structurally similar to triple-layered rotavirus particles as determined by cryogenic transmission electron microscopy. Two doses of aluminum hydroxide-adjuvanted G1 Ro-VLP (1 mu g, 5 mu g or 30 mu g), administered intramuscularly, elicited a robust homotypic neutralizing antibody response in rats. Also, rabbits administered G1 Ro-VLP (10 mu g or 30 mu g) four times intramuscularly with aluminum hydroxide adjuvant did not show any significant toxicity. Conclusions: Plant-derived Ro-VLP composed of VP7, VP6 and VP2 structural proteins would be a plausible alternative to live-attenuated oral rotavirus vaccines currently distributed worldwide. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study produced a monovalent Ro-VLP vaccine using a plant expression system and evaluated its immunogenicity and toxicological profile in animal models. The purified G1 Ro-VLP showed high purity and induced robust immune responses in rats and rabbits without significant toxicity, suggesting it as a potential alternative to current oral rotavirus vaccines.