Severe Acute Respiratory Syndrome Coronavirus Spike Protein Expressed by Attenuated Vaccinia Virus Protectively Immunizes Mice

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 101; no. 17; pp. 6641 - 6646
• Main Authors: Bisht, Himani, Roberts, Anjeanette, Vogel, Leatrice, Bukreyev, Alexander, Collins, Peter L., Murphy, Brian R., Subbarao, Kanta, Moss, Bernard
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 27.04.2004; National Acad Sciences
• Subjects: Animals; Antibodies; Biological Sciences; Cell Line; Coronavirus; Gene expression; HeLa Cells; Humans; Immunization; Lungs; Membrane Glycoproteins - genetics; Membrane Glycoproteins - immunology; Membrane Glycoproteins - physiology; Mice; Mice, Inbred BALB C; Microscopy, Confocal; Neutralizing antibodies; Proteins; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Rodents; SARS virus; SARS Virus - physiology; Severe acute respiratory syndrome; Spike Glycoprotein, Coronavirus; Turbinates; Vaccinia virus; Vaccinia virus - genetics; Viral Envelope Proteins - genetics; Viral Envelope Proteins - immunology; Viral Envelope Proteins - physiology; Viruses
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0401939101

The spike protein (S), a membrane component of severe acute respiratory syndrome coronavirus (SARS-CoV) is anticipated to be an important component of candidate vaccines. We constructed recombinant forms of the highly attenuated modified vaccinia virus Ankara (MVA) containing the gene encoding full-length SARS-CoV S with and without a C-terminal epitope tag called MVA/S-HA and MVA/S, respectively. Cells infected with MVA/S or MVA/S-HA synthesized a 200-kDa protein, which was recognized by antibody raised against a synthetic peptide of SARS-CoV S or the epitope tag in Western blot analyses. Further studies indicated that S was N-glycosylated and migrated in SDS polyacrylamide gels with an apparent mass of ≈160 kDa after treatment with peptide N-glycosidase F. The acquisition of resistance to endoglycosidase H indicated trafficking of S to the medial Golgi compartment, and confocal microscopy showed that S was transported to the cell surface. Intranasal or intramuscular inoculations of BALB/c mice with MVA/S produced serum antibodies that recognized the SARS S in ELISA and neutralized SARS-CoV in vitro. Moreover, MVA/S administered by either route elicited protective immunity, as shown by reduced titers of SARS-CoV in the upper and lower respiratory tracts of mice after challenge. Passive transfer of serum from mice immunized with MVA/S to naïve mice also reduced the replication of SARS-CoV in the respiratory tract after challenge, demonstrating a role for antibody to S in protection. The attenuated nature of MVA and the ability of MVA/S to induce neutralizing antibody that protects mice support further development of this candidate vaccine.