Antigenicity and immunogenicity of SARS-CoV S protein receptor-binding domain stably expressed in CHO cells.
The receptor-binding domain (RBD) of SARS coronavirus (SARS-CoV) spike (S) protein contains multiple conformation-dependent epitopes that induce neutralizing antibody responses. Here we used CHO-K1 cells to establish a cell line for stable expression of a 193-mer (residues 318-510) RBD (RBD193-CHO) and determined its antigenicity and immunogenicity. We found that RBD193-CHO reacted strongly with a panel of six monoclonal antibodies recognizing various conformational and linear epitopes in RBD, suggesting that this recombinant protein maintains intact conformation and good antigenicity. Immunization of mice with RBD193-CHO resulted in induction of high titers of RBD-specific neutralizing antibodies and potent IL-4-expressing T cell responses. RBD193-CHO induced immunity that protected a majority of the vaccinated mice from SARS-CoV challenge. These results suggest that the recombinant RBD produced in an established stable cell line maintains strong immunogenicity with high potential for use as an effective and economic subunit SARS vaccine.
Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10065, USA.
Lanying
L
Du
Guangyu
G
Zhao
Lin
L
Li
Yuxian
Y
He
Yusen
Y
Zhou
Bo-Jian
BJ
Zheng
Shibo
S
Jiang
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D015847:Interleukin-4 / Q000276:immunology; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D017434:Protein Structure, Tertiary; D011991:Receptors, Virus / Q000276:immunology; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000517:prevention & control; D064370:Spike Glycoprotein, Coronavirus; D013601:T-Lymphocytes / Q000276:immunology; D014611:Vaccination; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000276:immunology*
D000914:Antibodies, Viral; D008562:Membrane Glycoproteins; D011991:Receptors, Virus; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus; D015847:Interleukin-4