Vet World Vol.17 October-2024 Article - 13
Research Article
Veterinary World, 17(10): 2311-2321
https://doi.org/10.14202/vetworld.2024.2311-2321
Beyond traditional vaccines: Semi-purified low-pathogenic avian influenza H9N2 virus-like particles and their promise for broiler immunity
2. Department of Pathology, Faculty of Veterinary Science, University of Agriculture, Faisalabad, Pakistan.
Background and Aim: Avian influenza is a global threat to avian species, particularly in developing countries. Recombinant vaccines, including virus-like particles (VLPs), are promising strategies for preventing the spread of the disease. VLPs produced through the self-assembly of viral structural proteins without genomic material mimic native virions and are promising platforms for new vaccines. VLPs have been shown to elicit protective antibodies and are effective and safe vaccines against influenza. This study aimed to optimize the protocol for the production and characterization of H9N2 VLPs and their evaluation as a vaccine in broiler birds.
Materials and Methods: Low-pathogenic influenza virus (LPAI) H9N2 was isolated and characterized through whole-genome sequencing, and a VLP-based vaccine for LPAI H9N2 was prepared using a baculovirus expression system. Codon-optimized hemagglutinin (HA), neuraminidase (NA), and M1 were successfully cloned in pFastbac1 and expressed in SF9 cells. Proteins were characterized using sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE), western blotting, and electron microscopy after purification. Semi-purified proteins were tested as a vaccine in broiler chickens challenged with LPAI H9N2.
Results: Recombinant Bacmid DNA from positive clones was extracted and confirmed using a polymerase chain reaction. The transfection showed cytopathic effects, and the proteins were confirmed through western blotting and SDS-PAGE, which showed the sizes of HA = 62–64 KD, NA = 52 KD, and M1 = 25 KD. The shape and morphology were confirmed through transmission electron microscopy which revealed 100–150 nm size particles. As a result, the semi-purified VLPs (HA assay: 256) were tested as a vaccine for specific-pathogen free broiler birds; administered through subcutaneous and intranasal routes. The birds were challenged on the 28th day after vaccination with the H9N2 strain, and the birds showed significant cross-reactivity with the H9N2 strain.
Conclusion: The semi-purified VLP-based vaccine induced a significant immune response in vivo. This vaccine formulation has the potential to control avian influenza outbreaks in Pakistan’s poultry industry.
Keywords: avian influenza virus, baculovirus expression system, H9N2, recombinant vaccine, virus-like particles.
How to cite this article: Luqman M, Rahman SU, Gul ST, and Mahmood MS (2024) Beyond traditional vaccines: Semi-purified low-pathogenic avian influenza H9N2 virus-like particles and their promise for broiler immunity, Veterinary World, 17(10): 2311-2321.
Received: 2024-06-29 Accepted: 2024-09-17 Published online: 2024-10-17
Corresponding author: E-mail:
DOI: 10.14202/vetworld.2024.2311-2321
Copyright: Luqman, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
