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

The outbreak of Coronavirus Disease 2019(COVID-19)has posed a serious threat to global public health,calling for the development of safe and effective prophylactics and therapeutics against infection of its causative agent,severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),also known as 2019 novel coronavirus(2019-nCoV).The CoV spike(S)protein plays the most important roles in viral attachment,fusion and entry,and serves as a target for development of antibodies,entry inhibitors and vaccines.Here,we identified the receptor-binding domain(RBD)in SARS-CoV-2 S protein and found that the RBD protein bound strongly to human and bat angiotensin-converting enzyme 2(ACE2)receptors.SARS-CoV-2 RBD exhibited significantly higher binding affinity to ACE2 receptor than SARS-CoV RBD and could block the binding and,hence,attachment of SARS-CoV-2 RBD and SARS-CoV RBD to ACE2-expressing cells,thus inhibiting their infection to host cells.SARS-CoV RBD-specific antibodies could crossreact with SARS-CoV-2 RBD protein,and SARS-CoV RBD-induced antisera could cross-neutralize SARS-CoV-2,suggesting the potential to develop SARS-CoV RBD-based vaccines for prevention of SARS-CoV-2 and SARS-CoV infection.

Cross-neutralization of SARS coronavirus-specific antibodies against bat SARS-like coronaviruses

Dear Editor,The 2002–2003 global pandemic caused by severe acute respiratory syndrome coronavirus(SARS-CoV)infected around 8,000 people with 10%mortality(http://www.who.int/csr/sars/en/).The virus has a positivestranded RNA genome that encodes a large polyprotein(1a and 1ab),four structural proteins,including spike(S),

Development of a ferritin-based nanoparticle vaccine against the SARS-CoV-2 Omicron variant

Dear Editor,The COVID-19 pandemic has had a devastating effect on global health,resulting in over 6.2 million deaths worldwide.Continuous emergence of adaptive mutations of SARS-CoV-2 alters its pathogenicity and transmissibility,and renders its resistance to current vaccines and antiviral drugs.1 A new variant named Omicron discovered initially in South Africa has recently been proposed as a variant of concern(VOC)by the World Health Organization,because of its high transmissibility and resistance to current vaccines and therapeutic antibodies.2 Therefore,development of vaccines against prevalent variants including Omicron is urgently needed for COVID-19 prevention.

SARS-CoV-2 infection induces testicular injury in Rhesus macaque

Dear Editor,COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),which is the seventh coronavirus known to infect humans.The COVID-19 pandemic has spread to more than 200countries,with more than 600 million confirmed cases and over 6.5million deaths as of September 2022,posing a huge challenge to global public health.

T-cell immunity:a barrier to Omicron immune evasion

A recent study published in Cell by Naranbhai et al.disclosed that although the extent may vary,T-cell responses induced by infection by or vaccination against the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)are cross-reactive toward the Omicron variant in most individuals,highlighting the role T-cell immunity plays in preventing immune evasion by the Omicron and even future variants.