Human CellExp™ SARS-CoV-2 S1 (N501Y), Recombinant

SARS-CoV-2, the causative virus of COVID-19, uses the viral Spike (S) protein for host cell attachment and entry. The virus uses multiple host targets including the human protease Furin, Angiotensin converting enzyme 2 (ACE2), Neuropilin-1 (NRP1) and the transmembrane protease serine 2 (TMPRSS2) for host cell entry. The S protein has two domains S1 and S2, where S1 facilitates initial binding to the receptor and the S2 domain drives the membrane fusion and eventual entry of the virus. The S glycoprotein serves as an important target for monoclonal antibodies, entry inhibitors, and vaccines. Within the S1 protein, the conserved receptor-binding domain (RBD) binds with a high affinity for ACE2. Recently, increasing concern has been garnered over the discovery of new SARS-CoV-2 variants with the ability to escape antibody-mediated protection either by previous infection or vaccination. The N501Y mutation, which occurs in the RBD, is a substitution from an asparagine (N) to tyrosine (Y) at position 501. The N501Y mutation can be found in the B.1.1.7 (U.K), B.1.351 (South African) and P.1 (Brazil) strains. Currently, the U.K. variant is of the highest concern with known attributes including 50% increased transmission, increased severity based on hospitalizations and case fatality rates, and a moderate impact on neutralization by monoclonal antibody therapeutics and convalescent/post-vaccination sera.