Title:Immunogenicity and Protective Efficacy of Candidate Universal Influenza A Nanovaccines Produced in Plants by Tobacco Mosaic Virus-based Vectors
Volume: 19
Issue: 31
Author(s): Natalia V. Petukhova, Tatiana V. Gasanova, Liudmila A. Stepanova, Oxana A. Rusova, Marina V. Potapchuk, Alexandr V. Korotkov, Eugene V. Skurat, Liudmila M. Tsybalova, Oleg I. Kiselev, Peter A. Ivanov and Joseph G. Atabekov
Affiliation:
Keywords:
Influenza virus, M2e, plant, tobacco mosaic virus, coat protein fusion, chimeric particles, antibody response, protective antigens,
universal vaccine.
Abstract: A new approach for super-expression of the influenza virus epitope M2e in plants has been developed on the basis of a recombinant
Tobacco mosaic virus (TMV, strain U1) genome designed for Agrobacterium-mediated delivery into the plant cell nucleus. The
TMV coat protein (CP) served as a carrier and three versions of the M2e sequence were inserted into the surface loop between amino acid
residues 155 and 156. Cysteine residues in the heterologous peptide were thought likely to impede efficient assembly of chimeric particles.
Therefore, viral vectors TMV-M2e-ala and TMV-M2e-ser were constructed in which cysteine codons 17 and 19 of the M2e epitope
were substituted by codons for serine or alanine. Agroinfiltration experiments proved that the chimeric viruses were capable of systemically
infecting Nicotiana benthamiana plants. Antisera raised against TMV-M2e-ala virions appear to contain far more antibodies specific
to influenza virus M2e than those specific to TMV carrier particle (ratio 5:1). Immunogold electron microscopy showed that the
2-epitopes were uniformly distributed and tightly packed on the surface of the chimeric TMV virions. Apparently, the majority of the
TMV CP-specific epitopes in the chimeric TMV-M2e particles are hidden from the immune system by the M2e epitopes exposed on the
particle surface. The profile of IgG subclasses after immunization of mice with TMV-M2e-ser and TMV-M2e-ala was evaluated. Immunization
with TMV-M2e-ala induced a significant difference between the levels of IgG1 and IgG2a (IgG1/IgG2a=3.2). Mice immunized
with the chimeric viruses were resistant to five lethal doses (LD50) of the homologous influenza virus strain, A/PR/8/34 (H1N1) and
TMV-M2e-ala also gave partial protection (5LD50, 70% of survival rate) against a heterologous strain influenza A/California/04/2009
(H1N1) (4 amino acid changes in M2e). These results indicate that a new generation candidate universal nanovaccine against influenza
based on a recombinant TMV construct has been obtained.
