Characterization of the receptor-binding domain (RBD) of 2019 novel coronavirus: implication for development of RBD protein as a viral attachment inhibitor and vaccine

In this experimental study, the receptor binding domain (RBD) of SARS-CoV-2 S protein has been characterized and exhibits strong binding to its cell-associated and soluble ACE2 receptors with human and bat origin. 

This RBD protein also demonstrated significantly higher binding affinity to ACE2 than SARS-CoV RBD. SARS-CoV-2 RBD protein could block S protein-mediated SARS-CoV-2 pseudovirus and SARS-CoV pseudovirus entry into their respective ACE2 receptor-expressing target cells, constituting the basis of a future antiviral treatment.

Moreover, SARS-CoV RBD-induced antibodies could cross-react with SARS-CoV-2 RBD and cross-neutralize SARS-CoV-2 pseudovirus infection, suggesting another treatment option.

Either SARS-CoV RBD protein or SARS-CoV-2 RBD protein may be used as a candidate vaccine to induce cross-reactive or cross-neutralizing antibodies.