Acta Veterinaria et Zootechnica Sinica ›› 2021, Vol. 52 ›› Issue (12): 3569-3577.doi: 10.11843/j.issn.0366-6964.2021.012.023

• PREVENTIVE VETERINARY MEDICINE • Previous Articles     Next Articles

Evaluation of Immune Efficacy of H9 Subtype Avian Influenza Virus Inactivated Vaccine Based on Mosaic HA Sequence

LI Li1, TANG Guoyi1, FENG Helong1, XUE Yuhan1, REN Zhu1, WANG Guokang1, JIA Miaomiao1, SHANG Yu1,2,3, LUO Qingping1,2,3, SHAO Huabin1,2,3, WEN Guoyuan1,2,3*   

  1. 1. Institute of Animal Husbandry and Veterinary Sciences, Hubei Academy of Agricultural Sciences, Wuhan 430064, China;
    2. Key Laboratory of Prevention and Control Agents for Animal Bacteriosis (Ministry of Agriculture), Wuhan 430064, China;
    3. Hubei Provincial Key Laboratory of Livestock and Poultry Pathogen Microbiology, Wuhan 430064, China
  • Received:2021-03-16 Online:2021-12-25 Published:2021-12-22

Abstract: H9 subtype avian influenza is widely prevalent in poultry in China, which has caused huge economic losses to the poultry industry and also seriously threatened the public health safety. The high genetic variability of H9 subtype avian influenza virus (AIV) leads to poor antigenic matching between the circulating and vaccine strains, thus affecting the clinical protective effect of the vaccine. Therefore, it is urgent to develop a highly effective cross-protective vaccine against H9 subtype AIV. Mosaic vaccine is designed for the genetic diversity of pathogens by integrating all antigenic sequences to obtain a mosaic protein with the most extensive epitopes coverage, and to generate vaccine. In order to develop an efficient and universal H9 subtype avian influenza vaccine, a mosaic HA sequence of H9 AIV HAm/H9 was designed, optimized and synthesized according to the principles of mosaic vaccine. Utilizing the reverse genetic technology, a recombinant virus rPR8-HAm/H9 was constructed and rescued by replacing the HA segment of influenza virus PR8 strain (H1N1) with the HAm/H9 gene. The SPF chickens were immunized with the inactivated rPR8-HAm/H9 virus, and the effect of cross-protection was evaluated by detecting the antibody titer, the protection rate and viral shedding. The recombinant virus rPR8-HAm/H9 could induce high level of HI antibody and neutralizing antibody, as well as reduce virus shedding, and the protection rate against H9N2 AIV JM0305 strain was 80%. Our results showed that rPR8-HAm/H9 inactivated vaccine could provide efficient cross-protection against H9N2 AIV strain JM0305, and provided a preliminary basis for the research and development of universal vaccine for avian influenza based on mosaic technology.

Key words: avian influenza virus, H9 subtype, mosaic vaccine, cross protection

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