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ORIGINAL RESEARCH article

Front. Immunol.
Sec. Viral Immunology
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1513261
This article is part of the Research Topic Animal-borne viral disease: Pathogenesis, Innate immunity, Acquired immunity, and Novel vaccine development View all 6 articles

Partial protective efficacy of the current licensed Japanese Encephalitis live vaccine against the emerging genotype I Japanese Encephalitis Virus isolated from sheep

Provisionally accepted
Hailong Zhang Hailong Zhang 1Yan Zhang Yan Zhang 2*Dan Li Dan Li 2*Jiayang Zheng Jiayang Zheng 2*Junjie Zhang Junjie Zhang 2*Zongjie Li Zongjie Li 2Ke Liu Ke Liu 2Beibei Li Beibei Li 2Donghua Shao Donghua Shao 2Yafeng Qiu Yafeng Qiu 2Zhiyong Ma Zhiyong Ma 2*Jianchao Wei Jianchao Wei 2*Juxiang Liu Juxiang Liu 1*
  • 1 College of Veterinary Medicine, Hebei Agricultural University, Baoding, China
  • 2 Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China

The final, formatted version of the article will be published soon.

    Vaccination remains the most effective strategy for the prevention and control of Japanese encephalitis (JE). Seroconversion of the Japanese encephalitis virus (JEV) has been documented in sheep and goats across various countries, with sporadic fatal cases reported among sheep on farms in China. However, the efficacy of currently available attenuated live vaccines in protecting sheep remains uncertain. In this study, we utilized a mouse challenge model to conduct vaccination-challenge experiments aimed at assessing the protective efficacy of attenuated vaccines against genotype I JEV isolated from sheep. The neutralizing antibodies generated by the SA14-14-2 (GI) and SD12-F120 (GI) attenuated live vaccines were titrated. The results indicated that the specific neutralizing antibody titers against the sheep-derived SH2201 (GI) strain were significantly lower in mice immunized with the SA14-14-2 (GIII) vaccine compared to those receiving the SD12-F120 (GI) vaccine. Immunization of mice with high and medium doses of SA14-14-2 (GIII) vaccine completely protected against challenge with the homologous N28 (GIII) strain, but provide partial protection against challenge of heterologous SH2201 (GI) strain. After heterologous SH2201 (GI) challenge, mice immunized with medium and low doses of SA14-14-2 (GIII) vaccine exhibited different levels of viremia and characteristic encephalitis lesions. Meanwhile, immunization of mice with high and medium doses of SD12-F120 (GI) vaccine conferred 100% protection against the challenge of homologous SH2201 (GI) strain. In summary, while the currently licensed SA14-14-2 (GIII) attenuated live vaccines confer partial protection against sheep-derived GI strains, there is a pressing need for new vaccination strategies to effectively control infections across various genotypes and host species.

    Keywords: Japanese encephalitis virus, Sheep, SA14-14-2 vaccine, neutralizing antibodies, protective efficacy

    Received: 18 Oct 2024; Accepted: 29 Jan 2025.

    Copyright: © 2025 Zhang, Zhang, Li, Zheng, Zhang, Li, Liu, Li, Shao, Qiu, Ma, Wei and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Yan Zhang, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Dan Li, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Jiayang Zheng, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Junjie Zhang, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Zhiyong Ma, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Jianchao Wei, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
    Juxiang Liu, College of Veterinary Medicine, Hebei Agricultural University, Baoding, China

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