Cho Hyun-Kyu, Kang Yong-Myung, Sagong Mingeun, Kim Juhun, Kim Hyunjun, An Sungjun, Lee Youn-Jeong, Kang Hyun-Mi
Avian Influenza Research & Diagnostic Division, Animal and Plant Quarantine Agency, 177 Hyeoksin 8-ro, Gimcheon-si 39660, Republic of Korea.
Bioapp Institute, 394 Jigok-ro, Pohang-si 37668, Republic of Korea.
Vaccines (Basel). 2023 Feb 24;11(3):538. doi: 10.3390/vaccines11030538.
Prior to the identification of low pathogenic avian influenza H9N2 viruses belonging to the Y280 lineage in 2020, Y439 lineage viruses had been circulating in the Republic of Korea since 1996. Here, we developed a whole inactivated vaccine (vac564) by multiple passage of Y439 lineage viruses and then evaluated immunogenicity and protective efficacy in specific-pathogen-free chickens. We found that LBM564 could be produced at high yield in eggs (10EID/0.1 mL; 1024 hemagglutinin units) and was immunogenic (8.0 ± 1.2 log) in chickens. The vaccine showed 100% inhibition of virus in the cecal tonsil with no viral shedding detected in either oropharyngeal or cloacal swabs after challenge with homologous virus. However, it did not induce effective protection against challenge with heterologous virus. An imported commercial G1 lineage vaccine inhibited viral replication against Y280 and Y439 lineage viruses in major tissues, although viral shedding in oropharyngeal and cloacal swabs was observed up until 5 dpi after exposure to both challenge viruses. These results suggest that a single vaccination with vac564 could elicit immune responses, showing it to be capable of protecting chickens against the Y439 lineage virus. Thus, our results suggest the need to prepare suitable vaccines for use against newly emerging and re-emerging H9N2 viruses.
在2020年鉴定出属于Y280谱系的低致病性禽流感H9N2病毒之前，Y439谱系病毒自1996年以来一直在韩国流行。在此，我们通过Y439谱系病毒的多次传代开发了一种全灭活疫苗（vac564），然后在无特定病原体的鸡中评估其免疫原性和保护效力。我们发现LBM564能够在鸡蛋中高产（10EID/0.1 mL；1024血凝素单位），并且在鸡中具有免疫原性（8.0±1.2 log）。在用同源病毒攻击后，该疫苗在盲肠扁桃体中显示出100%的病毒抑制，在口咽或泄殖腔拭子中未检测到病毒脱落。然而，它并未诱导对异源病毒攻击的有效保护。一种进口的商业G1谱系疫苗在主要组织中抑制了针对Y280和Y439谱系病毒的病毒复制，尽管在接触两种攻击病毒后直到5 dpi在口咽和泄殖腔拭子中都观察到了病毒脱落。这些结果表明，单次接种vac564可引发免疫反应，表明其能够保护鸡免受Y439谱系病毒的侵害。因此，我们的结果表明需要制备适合用于对抗新出现和重新出现的H9N2病毒的疫苗。
