Efficient production of chimeric Human papillomavirus 16 L1 protein bearing the M2e influenza epitope in Nicotiana benthamiana plants

Abstract

BackgroundHuman papillomavirus 16 (HPV-16) L1 protein has the capacity to self-assemble into capsomers or virus-like particles (VLPs) that are highly immunogenic, allowing their use in vaccine production. Successful expression of HPV-16 L1 protein has been reported in plants, and plant-produced VLPs have been shown to be immunogenic after administration to animals.ResultsWe investigated the potential of HPV-16 L1 to act as a carrier of two foreign epitopes from Influenza A virus: (i) M2e2-24, ectodomain of the M2 protein (M2e), that is highly conserved among all influenza A isolates, or (ii) M2e2-9, a shorter version of M2e containing the N-terminal highly conserved epitope, that is common for both M1 and M2 influenza proteins. A synthetic HPV-16 L1 gene optimized with human codon usage was used as a backbone gene to design four chimeric sequences containing either the M2e2-24 or the M2e2-9 epitope in two predicted surface-exposed L1 positions. All chimeric constructs were transiently expressed in plants using the Cowpea mosaic virus-derived expression vector, pEAQ-HT. Chimeras were recognized by a panel of linear and conformation-specific anti HPV-16 L1 MAbs, and two of them also reacted with the anti-influenza MAb. Electron microscopy showed that chimeric proteins made in plants spontaneously assembled in higher order structures, such as VLPs of T = 1 or T = 7 symmetry, or capsomers.ConclusionsIn this study, we report for the first time the transient expression and the self-assembly of a chimeric HPV-16 L1 bearing the M2e influenza epitope in plants, representing also the first record of a successful expression of chimeric HPV-16 L1 carrying an epitope of a heterologous virus in plants. This study further confirms the usefulness of human papillomavirus particles as carriers of exogenous epitopes and their potential relevance for the production in plants of monovalent or multivalent vaccines.

Induction of Humoral and Cell-Mediated Immune Responses by Hepatitis B Virus Epitope Displayed on the Virus-Like Particles of Prawn Nodavirus

“…VLPs formed by the capsid proteins of viruses such as HBV (25,27,32) and human papillomavirus (33) and bacteriophages (8,34) have been widely used for displaying foreign epitopes for vaccine development. The carriers enhance the antigenicity of the fused epitopes (35)(36)(37), which are often found to be inefficient in eliciting immune responses.…”

Virus-Like Particles, a Versatile Subunit Vaccine Platform

“…Various plant viruses have demonstrated promise as recombinant antigen scaffolds, including alfalfa mosaic virus (AlMV) VLP containing epitopes from HIV-1 or rabies virus (Yusibov et al 2002 ), cowpea mosaic virus (CPMV) VLP containing epitopes from Bacillus anthracis (Phelps et al 2007 ) or HPV16 (Matic et al 2011 ) and tobacco mosaic virus (TMV) VLP containing epitopes for P. falciparum (Turpen et al 1995 ). The potential applications of chimeric VLPs extend far beyond the incorporation of epitopes from mammalian pathogens.…”

Plant-based vaccines against viruses

“…The insertion of a M2e 2-24 peptide in two different locations in the Human papillomavirus type 16 VLP-forming L1 protein has been reported [62], as has the use of surface display on a filamentous VLP-forming potexvirus CP [63], albeit without preclinical evaluation. However, a more recent investigation that used surface display on TMV virions was more noteworthy in that synthetic M2e peptides derived from a H1N1 virus inserted in between TMV U1 CP residues 155 and 156 were well displayed on virions.…”