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Protocol for Recombinant RBD-based SARS Vaccines: Protein Preparation, Animal Vaccination and Neutralization Detection
Published on: May 2, 2011
Intranasal immunization with recombinant Vaccinia virus encoding trimeric SARS-CoV-2 spike receptor-binding domain
Xiaoling Cao1, Junjie Zai2, Qingzhen Zhao3
1College of Life Science and Technology, Wuhan University of Bioengineering, Wuhan, China.
Abstract:
Respiratory transmission of SARS-CoV-2 is considered to be the major dissemination route for COVID-19, therefore, mucosal immune responses have great importance in preventing SARS-CoV-2 from infection. In this study, we constructed a recombinant Vaccinia virus (VV) harboring trimeric receptor-binding domain (RBD) of SARS-CoV-2 spike protein (VV-tRBD), and evaluated the immune responses towards RBD following intranasal immunization against mice and rabbits. In BALB/c mice, intranasal immunization with VV-tRBD elicited robust humoral and cellular immune responses, with high-level of both neutralizing IgG and IgA in sera against SARS-CoV-2 psudoviruses, and a number of RBD-specific IFN-γ-secreting lymphocytes. Sera from immunized rabbits also exhibited neutralization effects. Notably, RBD-specific secretory IgA (sIgA) in both nasal washes and bronchoalveolar lavage fluids (BALs) were detectable and showed substantial neutralization activities. Collectively, a recombinant VV expressing trimeric RBD confers robust systemic immune response and mucosal neutralizing antibodies, thus warranting further exploration as a mucosal vaccine.
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