Departmental Papers (Dental)

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Journal Article

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Plant Biotechnology Journal





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The WHO recommends complete withdrawal of oral polio vaccine (OPV) type 2 by April 2016 globally and replacing with at least one dose of inactivated poliovirus vaccine (IPV). However, high‐cost, limited supply of IPV, persistent circulating vaccine‐derived polioviruses transmission and need for subsequent boosters remain unresolved. To meet this critical need, a novel strategy of a low‐cost cold chain‐free plant‐made viral protein 1 (VP1) subunit oral booster vaccine after single IPV dose is reported. Codon optimization of the VP1 gene enhanced expression by 50‐fold in chloroplasts. Oral boosting of VP1 expressed in plant cells with plant‐derived adjuvants after single priming with IPV significantly increased VP1‐IgG1 and VP1‐IgA titres when compared to lower IgG1 or negligible IgA titres with IPV injections. IgA plays a pivotal role in polio eradication because of its transmission through contaminated water or sewer systems. Neutralizing antibody titres (~3.17–10.17 log2 titre) and seropositivity (70–90%) against all three poliovirus Sabin serotypes were observed with two doses of IPV and plant‐cell oral boosters but single dose of IPV resulted in poor neutralization. Lyophilized plant cells expressing VP1 stored at ambient temperature maintained efficacy and preserved antigen folding/assembly indefinitely, thereby eliminating cold chain currently required for all vaccines. Replacement of OPV with this booster vaccine and the next steps in clinical translation of FDA‐approved antigens and adjuvants are discussed.

Copyright/Permission Statement

This is the peer reviewed version of the following article:Chan, H., Xiao, Y., Weldon, W. C., Oberste, S. M., Chumakov, K., & Daniell, H. (2016). Cold chain and virus‐free chloroplast‐made booster vaccine to confer immunity against different poliovirus serotypes. Plant Biotechnology Journal, 14(11), 2190–2200., which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving


human infectious diseases, molecular farming, chloroplast transformation, bioencapsulation, oral delivery, mucosal immunity

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Dentistry Commons



Date Posted: 01 March 2022

This document has been peer reviewed.