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Immune response induced by oral administration with a Saccharomyces cerevisiae-based SARS-CoV-2 vaccine in mice
Tong Gao1, Yi Ren1, Shuangqin Li1
1College of Medicine, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
Background:
The global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlights the need to develop safe and effective vaccines with a top priority. Multiple vaccine candidates are under development, and several vaccines are currently available. Efforts need to be undertaken to counter the threat of the global COVID-19 pandemic.
Results:
We generated a Saccharomyces cerevisiae (S. cerevisiae)-based SARS-CoV-2 vaccine, EBY100/pYD1-RBD, in which the full-length receptor binding domain (RBD) of the spike protein of SARS-CoV-2 was expressed on the surface of yeast. Mice vaccinated orally with unadjuvanted EBY100/pYD1-RBD could produce significant humoral and mucosal responses as well as robust cellular immune responses. Notably, EBY100/pYD1-RBD elicited a mixed Th1/Th2-type cellular immune response with a Th1-biased immune response in a mouse model.
Conclusions:
Our findings highlight the importance of the RBD as a key target to design and develop vaccines against SARS-CoV-2 and provide evidence of oral administration of a S. cerevisiae-based SARS-CoV-2 vaccine eliciting significant immune responses. Most importantly, the S. cerevisiae surface display system can serve as a universal technology platform and be applied to develop other oral viral or bacterial vaccines.
Insights
A novel Saccharomyces cerevisiae-based vaccine targeting the SARS-CoV-2 receptor binding domain (RBD) successfully induced significant immune responses in mice following oral administration. This yeast-based platform shows promise for developing future oral vaccines against viral and bacterial threats.
Area of Science:
- Vaccinology
- Microbial Biotechnology
- Immunology
Background:
- The COVID-19 pandemic necessitates urgent development of safe and effective vaccines against SARS-CoV-2.
- Multiple vaccine strategies are in progress, emphasizing the need for innovative approaches.
Purpose of the Study:
- To develop and evaluate a novel oral vaccine candidate for SARS-CoV-2 using a yeast surface display system.
- To assess the immunogenicity of the S. cerevisiae-based vaccine expressing the SARS-CoV-2 receptor binding domain (RBD).
Main Methods:
- Generation of a Saccharomyces cerevisiae (S. cerevisiae) strain (EBY100/pYD1-RBD) displaying the full-length SARS-CoV-2 RBD on its surface.
- Oral vaccination of mice with the unadjuvanted S. cerevisiae-based vaccine.
- Analysis of humoral, mucosal, and cellular immune responses in vaccinated mice.
Main Results:
- Oral administration of the EBY100/pYD1-RBD vaccine elicited significant humoral and mucosal immune responses in mice.
- Robust cellular immune responses, including a mixed Th1/Th2 profile with a Th1 bias, were observed.
- The receptor binding domain (RBD) of SARS-CoV-2 was successfully expressed on the yeast surface.
Conclusions:
- The RBD is a critical target for designing effective SARS-CoV-2 vaccines.
- Oral administration of an S. cerevisiae-based vaccine can induce substantial immune responses.
- The S. cerevisiae surface display system offers a versatile platform for developing various oral vaccines.
