Immunization with the H5N1 Recombinant Vaccine Candidate Induces High Protection in Chickens against Vietnamese Highly Pathogenic Avian Influenza Virus Strains

Abstract

Vietnam is one of the countries most affected worldwide by the highly pathogenic avian influenza (HPAI) virus, which caused enormous economic loss and posed threats to public health. Over nearly two decades, with the antigenic changes in the diversified H5Ny viruses, the limited protective efficacy of the available vaccines was encountered. Therefore, it is necessary to approach a technology platform for the country to accelerate vaccine production that enables quick response to new influenza subtypes. This study utilized a powerful reverse genetics technique to successfully generate a recombinant H5N1 vaccine strain (designated as IBT-RG02) containing two surface proteins (haemagglutinin (HA) and neuraminidase (NA)) from the HPAI H5N1 (A/duck/Vietnam/HT2/2014(H5N1)) of the dominant clade 2.3.2.1c in Vietnam during 2012–2014. Importantly, the IBT-RG02 vaccine candidate has elicited high antibody titres in chickens (geometric mean titre (GMT) of 6.42 and 6.92, log2 on day 14 and day 28 p.i., respectively). To test the efficacy, immunized chickens were challenged with the circulating virulent strains. As results, there was a high protection rate of 91.6% chickens against the virulent A/DK/VN/Bacninh/NCVD-17A384/2017 of the same clade and a cross-protection of 83.3% against A/duck/TG/NAVET(3)/2013 virus of clade 1.1. Our promising results showed that we can independently master the reverse genetics technology for generation of highly immunogenic vaccine candidates, and henceforth, it is a timely manner to reformulate avian influenza virus vaccines against variable H5 clade HPAI viruses in Vietnam.

Re-evaluating efficacy of vaccines against highly pathogenic avian influenza virus in poultry: A systematic review and meta-analysis

“…After duplicate removal, 77 publications were screened, and 54 underwent full-text assessment. Ultimately, our dataset included data from 46 trials across 20 experimental studies [ [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] ], as detailed in Appendix Table 2. These trials collectively involved 863 SPF chickens.…”

Effects of Size and Surface Properties of Nanodiamonds on the Immunogenicity of Plant-Based H5 Protein of A/H5N1 Virus in Mice

“…The inactivated virus strain (IBT-RG02) was used for the HI assay. The IBT-RG02 strain was produced by reverse genetic technology using HA and neuraminidase (NA) proteins of the HPAI H5N1 (A/duck/Vietnam/HT2/2014(H5N1) of the clade 2.3.2.1c in the period 2012–2014 in Vietnam [ 20 ]. The HA amino acid sequence similarities between the synthetic H5.c2 and native H5 of A/duck/Vietnam/HT2/2014(H5N1) strains is 99.4%.…”

Modifying the hemagglutinin gene with the packaging signals to improve the ability of replication in eggs of IBT-RG02 vaccine virus strain

“…In a previous study, a recombinant H5N1 vaccine strain (designated as IBT-RG02 was successfully generated by a powerful reverse genetics technique that containing two surface proteins (haemagglutinin (HA) and neuraminidase (NA)) from the HPAI H5N1 (A/duck/Vietnam/HT2/2014(H5N1)) of the dominant clade 2.3.2.1c in Vietnam during 2012-2014 (Le, Nguyen, 2014;Hoang et al, 2020). This reverse genetics-based virus was utilized for use in this study.…”