Protection from SARS coronavirus conferred by live measles vaccine expressing the spike glycoprotein

Area of Science:

• Virology
• Vaccinology
• Immunology

Background:

• Reemergence of SARS-like coronaviruses poses a significant public health threat.
• Effective vaccines are needed to prevent transmission, particularly via aerosolized respiratory routes.

Purpose of the Study:

• To develop a live attenuated vaccine candidate for SARS-CoV using a measles virus (MV) vector.
• To evaluate the immunogenicity and protective efficacy of MV-based vaccines expressing SARS-CoV spike (S) protein.

Main Methods:

• Generation of recombinant measles virus (MV) candidates expressing either membrane-anchored full-length SARS-CoV spike (S) protein or its soluble ectodomain (Ssol).
• Immunization of mice susceptible to measles virus with recombinant MV candidates.
• Assessment of neutralizing antibody titers and protection against intranasal SARS-CoV challenge.

Main Results:

• Recombinant MV expressing the anchored full-length S protein induced the highest neutralizing antibody titers.
• Immunization with this candidate fully protected mice from SARS-CoV challenge.
• Compared to adjuvanted protein, MV induced stronger, Th1-biased immune responses.

Conclusions:

• Live attenuated measles virus vectors are effective for delivering SARS-CoV antigens.
• MV-based vaccines expressing SARS-CoV S protein can induce protective immunity and Th1-biased responses, desirable for antiviral vaccines.