Severe acute respiratory syndrome coronavirus spike protein expressed by attenuated vaccinia virus protectively immunizes mice.
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/Sor 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 approximately 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.
Bisht
Himani
H
Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Roberts
Anjeanette
A
Vogel
Leatrice
L
Bukreyev
Alexander
A
Collins
Peter L
PL
Murphy
Brian R
BR
Subbarao
Kanta
K
Moss
Bernard
B
D000818:Animals; D002460:Cell Line; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D045473:Severe acute respiratory syndrome-related coronavirus / Q000502:physiology*; D064370:Spike Glycoprotein, Coronavirus; D014616:Vaccinia virus / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*
D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins