Epitope mapping and biological function analysis of antibodies produced by immunization of mice with an inactivated Chinese isolate of SARS-CoV

Virology
Volume 334, Issue 1, 30 March 2005, Pages 134-143

Te-hui W. Chou, Shixia Wang, Pavlo V. Sakhatskyy, Innocent Mboudoudjeck, John M. Lawrence, Song Huang, Scott Coley, Baoan Yang, Jiaming Li, Qingyu Zhu, Shan Lu

Abstract

Inactivated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been tested as a candidate vaccine against the re-emergence of SARS. In order to understand the efficacy and safety of this approach, it is important to know the antibody specificities generated with inactivated SARS-CoV. In the current study, a panel of twelve monoclonal antibodies (mAbs) was established by immunizing Balb/c mice with the inactivated BJ01 strain of SARS-CoV isolated from the lung tissue of a SARS-infected Chinese patient. These mAbs could recognize SARS-CoV-infected cells by immunofluorescence analysis (IFA). Seven of them were mapped to the specific segments of recombinant spike (S) protein: six on S1 subunit (aa 12–798) and one on S2 subunit (aa 797–1192). High neutralizing titers against SARS-CoV were detected with two mAbs (1A5 and 2C5) targeting at a subdomain of S protein (aa 310–535), consistent with the previous report that this segment of S protein contains the major neutralizing domain. Some of these S-specific mAbs were able to recognize cleaved products of S protein in SARS-CoV-infected Vero E6 cells. None of the remaining five mAbs could recognize either of the recombinant S, N, M, or E antigens by ELISA. This study demonstrated that the inactivated SARS-CoV was able to preserve the immunogenicity of S protein including its major neutralizing domain. The relative ease with which these mAbs were generated against SARS-CoV virions further supports that subunit vaccination with S constructs may also be able to protect animals and perhaps humans. It is somewhat unexpected that no N-specific mAbs were identified albeit anti-N IgG was easily identified in SARS-CoV-infected patients. The availability of this panel of mAbs also provided potentially useful agents with applications in therapy, diagnosis, and basic research of SARS-CoV.

Keywords

SARS-CoV, Monoclonal antibody, Epitope mapping, Inactivated vaccine

Intranasal immunization with inactivated SARS-CoV (SARS-associated coronavirus) induced local and serum antibodies in mice

Vaccine
Volume 23, Issue 7, 4 January 2005, Pages 924-931

Di Qu, Bojian Zheng, Xin Yao, Yi Guan, Zheng-Hong Yuan, Nan-Shan Zhong, Li-Wei Lu, Jian-Ping Xie, Yu-Mei Wen

Abstract

SARS-CoV (severe acute respiratory syndrome-associated coronavirus) strain GZ50 was partially purified and inactivated with 1:2000 formaldehyde. In cell culture the inactivated virus blocked the replication of live virus by decreasing the TCID5.0 of the live virus 103.6 to 104.6 times. Inactivated GZ50 was used to immunize mice intranasally either alone, or after precipitation with polyethylene glycol (PEG), or with CpG, or CTB as an adjuvant. The titer of serum neutralizing antibodies was up to 1:640. In mice immunized with adjuvants or PEG precipitated GZ50, specific IgA was detected in tracheal-lung wash fluid by immunofluorescence. Though serum antibodies were detected, no anti-SARS-IgA could be detected in mice immunized only with inactivated GZ50. The roles of adjuvants in intranasal immunization with inactivated. SARS-CoV is discussed.

Keywords

SARS-CoV, Intranasal immunization, Inactivated vaccine