Anti-CoV-S2 domain (D8) antibody

General information on Anti-CoV-S2 domain (D8) antibody

SARS-CoV-2, the etiological agent of the COVID-19 disease, is known for its high infectivity and affinity towards the human cell surface receptor ACE2. The new strain of coronavirus interacts with the membrane-bound receptor through its complex spike protein which, in turn, consists of an N-terminal region (S1) and a C-terminal region (S2) subunit linked by a furin cleavage site.

The concerted action of the S1 and S2 subunits is deemed crucial for the high infection rate in the COVID-19 pathology. The S1 subunit carries the highly variable receptor-binding domain (RBD) which binds directly to the ACE2 receptor. However, despite the key role played by this subunit, the S2 domain of the spike is also crucial for infection. After S2 exposure driven by the proteolytic cleavage of the spike, this subunit suffers a major conformational change into the membrane fusion core which ultimately leads to fusion and viral internalization.

This reorganization happens spontaneously due to the presence of two identical and anti-parallel copies of the fusion peptide (heptad repeat, HR1 and HR2). Prior studies with MERS-CoV indicate that the S2 subunit and these repeats could potentially serve as biologically relevant targets for the study and treatment of SARS-CoV-2 infections.

The IgG anti-CoV-S2 (D8) antibody was isolated from a highly diverse pool of human antibodies from COVID-19 patients (LiAb-SFCOVID-19™) using phage display technologies and the recombinant form of the S2 protein. The specificity and binding affinity of the antibody towards the S2 subunit were confirmed in ELISA applications. Moreover, its stability and ease of production were verified in the transient mammalian system XtenCHO™.