Severe acute respiratory syndrome coronavirus nucleocapsid protein expressed by an adenovirus vector is phosphorylated and immunogenic in mice

1 Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada S7N 5E3 2 Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada L8N 3Z5 3 St Joseph's Hospital, Hamilton, ON, Canada L8N 4A6 Correspondence Alexander N. Zakhartchouk zakhartchouk{at}sask.usask.ca Severe acute respiratory syndrome coronavirus (SARS-CoV) has been identified as the aetiological agent of SARS. Thus, vaccination against SARS-CoV may represent an effective approach towards controlling SARS. The nucleocapsid (N) protein is thought to play a role in induction of cell-mediated immunity to SARS-CoV and thus it is important to characterize this protein. In the present study, an E1/partially E3-deleted, replication-defective human adenovirus 5 (Ad5) vector (Ad5-N-V) expressing the SARS-CoV N protein was constructed. The N protein, expressed in vitro by Ad5-N-V, was of the expected molecular mass of 50 kDa and was phosphorylated. Vaccination of C57BL/6 mice with Ad5-N-V generated potent SARS-CoV-specific humoral and T cell-mediated immune responses. These results show that Ad5-N-V may potentially be used as a SARS-CoV vaccine.