A subunit vaccine, RBD-S, is under development to prevent severe acute respiratory syndrome (SARS) caused by SARS coronavirus (SARS-CoV), which is classified by the U.S. NIH as a category C pathogen. This vaccine is comprised of a recombinant receptor-binding domain (RBD) of the SARS-CoV spike (S) protein and its current formulation is being evaluated. The vaccine would induce neutralizing antibodies. Variants of RBD-S were compared for their antigenicity, functionality and immunogenicity in mice. We found that a deglycosylated variant, RBD219-N1 exhibited high expression yield, and maintained the antigenicity and functionality of the wild-type protein. More importantly, RBD219-N1 induced significantly stronger RBD-specific antibody responses and a higher level of neutralizing antibodies in immunized mice than the wild-type.

Vaccine development is being led by a product development partnership and research is being effected at Texas Children’s Hospital Center for Vaccine Development in collaboration with two academic partners (the New York Blood Center and University of Texas Medical Branch).