The expression in plants of an engineered VP2 protein of Infectious Bursal Disease Virus induces formation of structurally heterogeneous particles that protect from a very virulent viral strain

PLoS One. 2021 Feb 16;16(2):e0247134. doi: 10.1371/journal.pone.0247134. eCollection 2021.

Abstract

Infectious Bursal Disease Virus (IBDV), the etiological agent of Gumboro disease, causes mortality and immunosuppression in chickens and major losses to poultry industry worldwide. The IBDV major capsid protein VP2 is considered the best candidate for the production of novel subunit vaccines. This structural protein contains the major conformational epitopes responsible for the induction of IBDV neutralizing antibodies in chickens and has been demonstrated able to form supramolecular structures in yeast and insect cells. The aim of this study was to express an engineered version of the VP2 protein (His-pVP2) to verify its ability to self-assemble into virus-like particles in plants. The recombinant VP2 was transiently expressed by agroinfiltration in Nicotiana benthamiana and transmission electron microscopy of sucrose density gradient fractions revealed the presence of a mixed population of differently shaped particles ranging from spherical capsids, with a diameter between ~25 and ~70 nm, to tubular structures, with variable length (from 100 to 400 nm). The recombinant VP2-based particles when used for the intramuscular immunization of specific-pathogen-free chicks resulted able to induce the production of anti-IBDV specific antibodies at titers comparable to those induced by a commercial vaccine. Moreover, all the immunized birds survived to the challenge with a Moroccan very virulent IBDV strain with no major histomorphological alterations of the Bursa of Fabricius, similarly to what obtained with the commercial inactivated vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Capsid / metabolism
  • Chickens
  • Enzyme-Linked Immunosorbent Assay
  • Infectious bursal disease virus / genetics
  • Infectious bursal disease virus / pathogenicity*
  • Microscopy, Electron, Transmission
  • Nicotiana / genetics
  • Nicotiana / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism*
  • Virulence / genetics
  • Virulence / physiology

Substances

  • Recombinant Proteins

Grants and funding

This work was funded by AVIAMED project through the ARIMNet2 2015 Call by the following funding agencies: Italian Ministry of Agricultural, Food and Forestry Policies (MIPAAF) and Ministry of Higher Education, Scientific Research and Professional Training of Morocco (MESRSFC). ARIMNet2 (ERA-NET) has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 618127/182. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.