Universal subunit vaccine protects against multiple SARS-CoV-2 variants and SARS-CoV

Area of Science:

• Virology
• Immunology
• Vaccine Development

Background:

• The spike protein's conserved backbone region offers a potential target for broad-spectrum coronavirus vaccines.
• Omicron variants of SARS-CoV-2 possess numerous mutations, particularly in the Receptor Binding Domain (RBD).

Purpose of the Study:

• To design and evaluate novel subunit vaccines based on a conserved SARS-CoV-2 spike protein backbone.
• To assess the immunogenicity and cross-protective efficacy of these vaccines against diverse SARS-CoV-2 variants and SARS-CoV.

Main Methods:

• Designed four subunit vaccines: S-6P-no-RBD, S-6P-Delta-RBD, S-6P-BA5-RBD, and S-6P-WT-RBD.
• Evaluated vaccine-induced neutralizing antibodies and protective efficacy in mouse models against various SARS-CoV-2 variants and SARS-CoV.

Main Results:

• The S-6P-Delta-RBD vaccine induced potent neutralizing antibodies against all tested SARS-CoV-2 variants, including Omicron subvariants.
• This vaccine demonstrated complete protection against lethal challenge with SARS-CoV-2 Delta and SARS-CoV in mice.
• Vaccinated mouse sera conferred protection to naive mice against Delta variant challenge, reducing viral load and pathology.

Conclusions:

• The S-6P-Delta-RBD vaccine shows promise as a universal COVID-19 vaccine candidate.
• This vaccine may also serve as a pan-sarbecovirus vaccine to combat current and future coronavirus outbreaks.