（阅读原文）
University of Chinese Academy of Sciences, China.
Liverna Therapeutics Inc., Zhuhai, China
摘要
新冠病毒对全球公共健康造成了持续性威胁，已上市多种疫苗，并在预防感染、特别是重症和死亡取得了巨大成功。然而，随着新变种的不断出现，已出现突破性感染，有必要开发广谱疫苗。二价或多价疫苗是一种广谱疫苗开发策略。在本文中，我们研究了Delta/BA.5二价疫苗在K18-hACE2小鼠和仓鼠体内对Delta和BA.5病毒的有效性，结果表明Delta/BA.5疫苗免疫后可产生高水平中和抗体，并使动物免受Delta和BA.5病毒的感染；此外，动物免疫血清对其它多种突变体的活病毒或假病毒（如WIV04、BA.2、BF.7、CH1.1、BQ.1.1、XBB.1.5、XBB.1.9、EG.5和JN.1）均有中和活性，表明Delta/BA.5二价mRNA疫苗具有广谱潜力，为未来的广谱疫苗设计提供了有用信息。
Fig. 1. Delta/BA.5 bivalent mRNA vaccine protects K18-hACE2 mice and hamsters from infection. K18-hACE2 mice (A to G) and hamsters (H to N) were intramuscularly immunized twice on Day 0 and 28 (A and H). Spike protein specific antibody was measured with ELISA after immunization and prior to challenge (B and I); neutralizing antibody was determined against the authentic or pseudotyped viruses (C and J). After being challenged with BA.5, some mice in each group were sacrificed on 4 dpi, and live virus (D) and viral RNA (E) were determined in respiratory tissues (n = 8); some mice were kept until 14 dpi for weight loss (F) and mortality (G) observation (n = 6 or 8). Half of the hamsters in each group were challenged with Delta and killed on 4 dpi (K and L), and the other half with BA.5 and killed on 3 dpi (M and N) for virus detection. Dotted lines indicate the limit of detection.
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