Since the primary goal of our study was to investigate whether combining the appropriate amount of VP3 with the 71VG formulation could reduce the antigen dosage while achieving superior clinical benefits, we did not design the study to compare adjuvanted VLP vaccine with an unadjuvanted control. responses in chickens with inactivated RG6 compared to unadjuvanted inactivated disease. While increasing antigen dose enhanced 71VG adjuvanted RG6-induced antibody titers, the vaccine displayed minimal cross-reactivity against locally circulating HPAI H5N2. In contrast, H5N2-VLP comprising the HA protein of clade 2.3.4.4c, adjuvanted with (FMDV) VP3 in 71VG, significantly promoted Hi there antibody reactions. All H5N2-VLP immunized chickens survived lethal difficulties with the local clade 2.3.4.4c H5 strain. == Pi-Methylimidazoleacetic acid Summary == The study shown the immunogenic potential of the VLP vaccine in chickens. Our findings present insights for optimizing VLP vaccines, permitting the incorporation of the HA of currently circulating H5 viruses to efficiently Pi-Methylimidazoleacetic acid mitigate the effect of the rapidly growing clade 2.3.4.4 H5 outbreaks. Keywords:Highly pathogenic avian influenza (HAPI), H5N2 subtype, Chicken, Poultry vaccination, Virus-like particles == Intro == Since the emergence of the highly pathogenic avian influenza (HPAI) A (H5) viruses, specifically the A/Goose/Gaundong/01/1996 (Gs/GD) lineage in 1996, they have undergone rapid development into ten phylogenetic clades (0 to 9) and multiple subclades[1]. The clade 2.3.4.4 H5 HPAI viruses have caused more than 541 million parrots culled as of January 5, 2024, in response to the outbreak[2],[3],[4]. According to the World Health Corporation (WHO), as of January 5, 2024, there have been 880 human infections and 460 deaths caused by H5N1[5]. The onward and considerable transmission of HPAI H5Nx viruses among vulnerable avian hosts poses a threat of novel HPAI disease emergence and increases concerns about human being pandemic illness. In recent outbreaks, there were more than 3,663 H5 HPAI outbreaks across Europe, Asia, and Africa from 2020 to 2021, and nearly 5,212 H5 HPAI outbreaks from 2022 to 2024 occurred in unvaccinated countries in Europe, Asia, Africa, and North America[6]. Taiwan experienced its largest epidemic of H5 HPAI outbreak in poultry in history in 2015, impacting 944 poultry farms and resulting in the death or culling of more than 4.15 million geese[7],[8]. Given the quick mutations and global distribution of clade 2.3.4.4 H5 viruses, there is an increasing need to apply mass immunization of poultry, including ring vaccination strategies, to effectively contain the virus’s spread. However, significant issues concerning the implementation of vaccines in poultry include disease escape due to Pi-Methylimidazoleacetic acid incomplete sterilization of inactivated viral vaccines, viral survival from vaccine-induced herd immunity, and further evolution. Additionally, it is challenging SAPK Pi-Methylimidazoleacetic acid to distinguish antibodies derived from vaccination or natural infection. To address these concerns, we have developed a recombinant VLP platform that is devoid of the viral genome, easy for updating the HA gene relating to circulating disease strains, and amenable to the mass production of vaccines for any vast number of susceptible parrots[9]. By using this flexible platform, conducted in the biosafety level one, we generated an H5N2-VLP vaccine comprising the HA gene from your A/Goose/Taiwan/01004/2015 (clade 2.3.4.4c) strain[8]. We assessed its immunogenicity and cross-clade safety in chicken hosts. In addition, we compared the results with Pi-Methylimidazoleacetic acid chickens immunized with inactivated H5N1 whole disease derived from IBCDC-RG6 (A/Anhui/1/2005), a candidate vaccine disease belonging to clade 2.3.4[10]. The findings highlight the potential of VLPs like a vaccine platform for rapidly producing epidemic-strain matched vaccines against zoonotic influenza disease infections. == Materials & Methods == == Cells and viruses == Epithelial Madin-Darby canine kidney (MDCK) cells (ATCC CCL-34) were cultured in Dulbeccos revised Eagles medium (DMEM) supplemented with 10 %10 % fetal bovine serum (FBS) and antibiotics. A monolayer of.