SARS-CoV-2 Spike Protein S1 Subunit Rabbit Monoclonal Antibody Development Service

We immunized rabbits with SARS-CoV-2 S protein S1 subunit, then did single B cell sorting and culturing. There will be about 70 ul supernatant per well (clonal single B cell). If you are interested in rabbit monoclonal antibodies against SARS-CoV-2 Spike protein especially the S1 subunit or RBD (receptor binding domain), we can send you some supernatant for quick screening. Then you tell us which single B cell clone you like. We sequence the antibody VH/VL and produce recombinant rabbit single B cell for your confirmation. You can pay for the antibody or the clone with discount or exclusive right.

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Background

The S1 subunit of the SARS-CoV-2 (2019-nCoV) spike (S) glycoprotein plays the most important roles in viral attachment, fusion and entry, and serves as a target for development of virus entry inhibitors, neutralizing antibodies, and vaccines. There are two subunits, S1 and S2, in the SARS-CoV-2 spike (S) glycoprotein. The S1 subunit, the N-terminal 14–685 amino acids of S protein, contains N-terminal domain (NTD), receptor binding domain (RBD), and receptor binding motif (RBM). The SARS-CoV and SARS-CoV-2 S proteins mediate viral entry into host cells by binding to a host receptor, angiotensin-converting enzyme 2 (ACE2), through RBD in the S1 subunit, and then fusing the viral and host membranes through the S2 subunit.

The SARS-CoV-2 S1 subunit especially its RBD has become a popular target of antibodies for diagnostics test and proteins and antibodies for therapeutic drugs. The amino-acid sequence identity is around 74% between the RBDs in the SARS-CoV and SARS-CoV-2 spike proteins, similar to the 77% identity between the whole spike proteins of SARS-CoV and SARS-CoV-2. Such a high degree of sequence similarity raises the possibility that cross-reactive epitopes may exist. Although the SARS-CoV RBD polyclonal antibodies can recognize both viruses, it was reported that only one published RBD monoclonal antibodies neutralizing SARS-CoV bound to SARS-CoV-2 spike RBD. Out of the 28 residues in the epitope of the S1 RBD monoclonal antibody, only 4 residues (86%) in SARS-CoV-2 are different from SARS-CoV. However, the S1 RBD mAb binds to SARS-CoV spike RBD (Kd = 1 nM) with a much higher affinity than to SARS-CoV-2 spike RBD (Kd = 115 nM, or 6.3 nM measured by another lab). Thus, it is important and possible to develop SARS-CoV-2 specific monoclonal antibodies using SARS-CoV-2 Spike protein, its S1 subunit, or RBD with binding and even neutralizing functions.