A Subunit-based Influenza/SARS-CoV-2 Omicron Combined Vaccine Induced Potent Protective Immunity in BALB/c Mice
Naru Zhang1,#, Zihui Ye1,#, Cun Li2,#, Jie Zhou3,#, Wei Xue2, Luying Xiang1, Yuewen Chen1, Shuchang Chen1, Rouhan Ye1, Jingyin Dong1, Jie Zhou2,*, Shibo Jiang3,*, Haijun Han1,*
1 School of Medicine, Hangzhou City University, Hangzhou 310015, China
2 Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
3 Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), Shanghai Frontiers Science Center of Pathogenic Microbes and Infection, School of Basic Medical Sciences, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai 200032, China
*Correspondence: Jiezhou@hku.hk(J.Z.);shibojiang@fudan.edu.cn(S.J.); hanhj@hzcu.edu.cn (H.H.)
Abstract: Infection with influenza A virus (IAV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a significant risk to human life, health, and the global economy. Vaccination is one of the most effective strategies in the fight against infectious viruses. In this study, we, for the first time, have evaluated the immunogenicity and protective effect of an influenza/SARS-CoV-2 Omicron subunit combined vaccine adjuvanted with MF59 and administered to BALB/c mice. Results showed that the combined vaccine induced high levels of IgG, IgG1, and IgG2a antibodies, as well as influenza A H1N1/California/2009 virus-specific hemagglutination-inhibiting antibodies in BALB/c mice. Moreover, this subunit combined vaccine induced high titers of neutralization antibodies against SARS-CoV-2 Omicron BA.5 pseudovirus and effectively reduced the viral load of authentic SARS-CoV-2 Omicron BA.5.2 variant in the cell culture supernatants. These results suggested that this subunit combined vaccine achieved protective effect against both H1N1 A/California/07/2009 strain and SARS-CoV-2 Omicron BA.5.2 variant. It is therefore expected that this study will establish the scientific foundation for the next-step development of combined vaccines against other strains or variants of IAV and SARS-CoV-2.
Keywords: Influenza A virus; SARS-CoV-2; Omicron BA.5; MF59; subunit vaccines