Inactivated SARS-CoV vaccine elicits high titers of spike protein-specific antibodies that block receptor binding and virus entry

Biochemical and Biophysical Research Communications
Volume 325, Issue 2, 10 December 2004, Pages 445-452

Yuxian He, Yusen Zhou, Pamela Siddiqui, Shibo Jiang

Abstract

The only severe acute respiratory syndrome (SARS) vaccine currently being tested in clinical trial consists of inactivated severe acute respiratory syndrome-associate coronavirus (SARS-CoV). However, limited information is available about host immune responses induced by the inactivated SARS vaccine. In this study, we demonstrated that SARS-CoV inactivated by β-propiolactone elicited high titers of antibodies in the immunized mice and rabbits that recognize the spike (S) protein, especially the receptor-binding domain (RBD) in the S1 region. The antisera from the immunized animals efficiently bound to the RBD and blocked binding of RBD to angiotensin-converting enzyme 2, the functional receptor on the susceptible cells for SARS-CoV. With a sensitive and quantitative single-cycle infection assay using pseudovirus bearing the SARS-CoV S protein, we demonstrated that mouse and rabbit antisera significantly inhibited S protein-mediated virus entry with mean 50% inhibitory titers of 1:7393 and 1:2060, respectively. These data suggest that the RBD of S protein is a major neutralization determinant in the inactivated SARS vaccine which can induce potent neutralizing antibodies to block SARS-CoV entry. However, caution should be taken in using the inactivated SARS-CoV as a vaccine since it may also cause harmful immune and/or inflammatory responses.

Keywords

SARS-CoV, Vaccine, Spike protein, Receptor-binding domain, Antibodies

Prevalence of canine coronavirus antibodies by an enzyme-linked immunosorbent assay in dogs in the south of Italy

Journal of Virological Methods
Volume 102, Issues 1–2, April 2002, Pages 67-71

Annamaria Pratelli, Gabriella Elia, Vito Martella, Alessandra Palmieri, Francesco Cirone, Antonella Tinelli, Marialaura Corrente, Canio Buonavoglia

Abstract

An enzyme-linked immunosorbent assay (Elisa), using as antigen canine coronavirus-infected CrFK cell supernatant, was developed to detect antibodies against canine coronavirus (CCoV). Out of a total of 109 dog serum samples, 80 which were positive by routine virus neutralisation test were also Elisa positive. Seventeen samples which were negative by the virus neutralisation test, were positive by Elisa and by the confirmatory Western blotting test. The Elisa was substantially more sensitive than the virus neutralisation test in detecting antibodies to CCoV and may be used as an alternative technique to virus neutralisation.

Keywords

Dog, Coronavirus, Antibodies, Elisa