A recombinant baculovirus-expressed S glycoprotein vaccine elicits high titers of SARS-associated coronavirus (SARS-CoV) neutralizing antibodies in mice.
A recombinant SARS-CoV spike (S) glycoprotein vaccine produced in insect cells in a pre-clinical development stage is described. A truncated version of S glycoprotein, containing only the ecto-domain, as well as a His-tagged full-length version were cloned and expressed in a serum-free insect cell line, ExpresSF+. The proteins, purified to apparent homogeneity by liquid column chromatography, were formulated without adjuvant at 3, 9, 27, and 50 microg per dose in phosphate saline and used to immunize mice. Both antigens in each formulation elicited a strong immune response after two or three vaccinations with the antigen. Neutralizing antibody titers correlated closely with standard ELISA reactivity against the S glycoprotein. The truncated S protein was also formulated with an adjuvant, aluminum hydroxide, at 1 microg per dose (+/-adjuvant), and 5 microg per dose (+/-adjuvant). Significantly enhanced immune responses, manifested by higher titers of serum ELISA and viral neutralizing antibodies, were achieved in adjuvanted groups with fewer doses and lower concentration of S glycoprotein. These findings indicate that the ecto-domain of SARS-CoV S glycoprotein vaccine, with or without adjuvant, is immunogenic and induces high titers of virus neutralizing antibodies to levels similar to those achieved with the full S glycoprotein vaccine.
Protein Sciences Corporation, 1000 Research Parkway, Meriden, CT 06540, USA. zzhou@proteinsciences.com
Zhimin
Z
Zhou
Penny
P
Post
Rick
R
Chubet
Katherine
K
Holtz
Clifton
C
McPherson
Martin
M
Petric
Manon
M
Cox
D000536:Aluminum Hydroxide / Q000494:pharmacology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D016367:Baculoviridae / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D064370:Spike Glycoprotein, Coronavirus; D014614:Vaccines, Synthetic / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; D000536:Aluminum Hydroxide