title: Yeast-expressed recombinant protein of the receptor-binding domain in SARS-CoV spike protein with deglycosylated forms as a SARS vaccine candidate.
abstract: Development of vaccines for preventing a future pandemic of severe acute respiratory syndrome (SARS) caused by SARS coronavirus (SARS-CoV) and for biodefense preparedness is urgently needed. Our previous studies have shown that a candidate SARS vaccine antigen consisting of the receptor-binding domain (RBD) of SARS-CoV spike protein can induce potent neutralizing antibody responses and protection against SARS-CoV challenge in vaccinated animals. To optimize expression conditions for scale-up production of the RBD vaccine candidate, we hypothesized that this could be potentially achieved by removing glycosylation sites in the RBD protein. In this study, we constructed two RBD protein variants: 1) RBD193-WT (193-aa, residues 318-510) and its deglycosylated forms (RBD193-N1, RBD193-N2, RBD193-N3); 2) RBD219-WT (219-aa, residues 318-536) and its deglycosylated forms (RBD219-N1, RBD219-N2, and RBD219-N3). All constructs were expressed as recombinant proteins in yeast. The purified recombinant proteins of these constructs were compared for their antigenicity, functionality and immunogenicity in mice using alum as the adjuvant. We found that RBD219-N1 exhibited high expression yield, and maintained its antigenicity and functionality. More importantly, RBD219-N1 induced significantly stronger RBD-specific antibody responses and a higher level of neutralizing antibodies in immunized mice than RBD193-WT, RBD193-N1, RBD193-N3, or RBD219-WT. These results suggest that RBD219-N1 could be selected as an optimal SARS vaccine candidate for further development.
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Wen-Hsiang
authors.initials: WH
authors.lastname: Chen
authors.affiliation: Lindsley F Kimball Research Institute; New York Blood Center; New York, NY USA.
authors.forename: Lanying
authors.initials: L
authors.lastname: Du
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Shivali M
authors.initials: SM
authors.lastname: Chag
authors.affiliation: Lindsley F Kimball Research Institute; New York Blood Center; New York, NY USA.
authors.forename: Cuiqing
authors.initials: C
authors.lastname: Ma
authors.affiliation: Lindsley F Kimball Research Institute; New York Blood Center; New York, NY USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Tricoche
authors.affiliation: Department of Microbiology and Immunology; University of Texas Medical Branch; Galveston, TX USA.
authors.forename: Xinrong
authors.initials: X
authors.lastname: Tao
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Seid
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Elissa M
authors.initials: EM
authors.lastname: Hudspeth
authors.affiliation: Lindsley F Kimball Research Institute; New York Blood Center; New York, NY USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Lustigman
authors.affiliation: Department of Microbiology and Immunology; University of Texas Medical Branch; Galveston, TX USA.
authors.forename: Chien-Te K
authors.initials: CT
authors.lastname: Tseng
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Maria Elena
authors.initials: ME
authors.lastname: Bottazzi
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hotez
authors.affiliation: Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhan
authors.affiliation: Lindsley F Kimball Research Institute; New York Blood Center; New York, NY USA; Key Laboratory of Medical Molecular Virology of MOE/MOH; Shanghai Medical College and Institute of Medical Microbiology; Fudan University; Shanghai, PR China.
authors.forename: Shibo
authors.initials: S
authors.lastname: Jiang
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds / Q000008:administration & dosage; D000818:Animals; D005260:Female; D015870:Gene Expression; D006031:Glycosylation; D008807:Mice, Inbred BALB C; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D064370:Spike Glycoprotein, Coronavirus / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D011994:Recombinant Proteins; D064370:Spike Glycoprotein, Coronavirus; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; C041524:aluminum sulfate
keywords: SARS-CoV; deglycosylation; receptor-binding domain; vaccine; yeast expression