Development of SARS-CoV-2 animal vaccines using a stable and efficient NDV expression system

Area of Science:

• Veterinary Virology
• Immunology
• Vaccine Development

Background:

• The ongoing coronavirus disease 2019 (COVID-19) pandemic and the emergence of SARS-CoV-2 variants necessitate urgent control measures.
• Various animal species are susceptible to SARS-CoV-2 infection, posing a risk of becoming viral reservoirs.
• Animal vaccination is essential to prevent SARS-CoV-2 spillover and the establishment of animal reservoirs.

Purpose of the Study:

• To establish an efficient Newcastle disease virus (NDV)-vectored system for rapid vaccine generation against SARS-CoV-2 in animals.
• To evaluate the immunogenicity of NDV-vectored SARS-CoV-2 vaccines in a preclinical animal model.

Main Methods:

• Development of recombinant NDV (rNDV) vectors expressing the SARS-CoV-2 spike (S) or S1 protein.
• Confirmation of S and S1 protein expression and incorporation into viral particles.
• Immunization of mice via intramuscular (rNDV-S) or intranasal (rNDV-S1) routes.
• Assessment of humoral (antibody) and cellular (T-cell) immune responses.

Main Results:

• Efficient expression of SARS-CoV-2 S and S1 proteins by rNDV vectors.
• Incorporation and surface display of the S protein on rNDV-S viral particles.
• Intramuscular immunization with rNDV-S elicited robust binding and neutralizing antibodies, along with a strong S-specific T-cell response.
• Intranasal immunization with rNDV-S1 induced a potent T-cell response but minimal antibody production.

Conclusions:

• NDV-vectored vaccine candidates effectively induce both humoral and cellular immunity against SARS-CoV-2.
• The developed NDV-vectored system provides a versatile platform for creating vaccines targeting antibody and T-cell responses.
• This approach offers a promising strategy for controlling SARS-CoV-2 in susceptible animal populations.