Intranasal Sendai virus-based SARS-CoV-2 vaccine using a mouse model

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• The COVID-19 pandemic necessitates effective vaccination strategies.
• Intranasal vaccines and booster immunizations are gaining attention for SARS-CoV-2.
• Developing novel delivery methods for vaccines is crucial.

Purpose of the Study:

• To develop and evaluate an intranasal vaccine for SARS-CoV-2.
• To assess the immunogenicity of a Sendai virus-based intranasal vaccine.
• To determine the efficacy of booster immunization with the intranasal vaccine.

Main Methods:

• Developed an intranasal vaccine using a receptor binding domain (RBD) of the SARS-CoV-2 spike protein (S-RBD) antigen within an F-deficient Sendai virus vector.
• Administered the S-RBD-loaded Sendai virus vector intranasally to mice.
• Administered a booster dose at week 8.
• Measured S-RBD-specific IgM, IgG, and IgA antibody titers in serum and bronchoalveolar lavage fluid (BALF).
• Assessed neutralizing antibody responses against a pseudotyped lentivirus expressing the SARS-CoV-2 spike protein.

Main Results:

• Intranasal administration of the S-RBD-loaded Sendai virus vector induced S-RBD-specific IgM, IgG, and IgA antibody responses in serum and BALF for 12 weeks.
• A booster dose at week 8 significantly increased neutralizing antibody titers in serum and BALF by week 12.
• The induced antibodies demonstrated neutralization capacity against SARS-CoV-2 spike protein-mediated viral entry.

Conclusions:

• The developed Sendai virus-based intranasal vaccine is effective in inducing humoral and neutralizing immune responses against SARS-CoV-2.
• Intranasal vaccination with a booster dose enhances protective antibody levels.
• This intranasal vaccine platform shows potential for preventing COVID-19.