The expression, purification, and characterization of 6B1 monoclonal antibody against SARS-CoV-2 Spike glycoprotein

Abstract

In late 2019, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was identified and announced as a pandemic. It is a zoonotic disease that originated from bats and causes severe pneumonia and acute respiratory distress syndrome (ARDS) in humans. The virus binds to the host receptor angiotensin converting enzyme-2 (ACE2) via its trimeric spike glycoprotein. The spike glycoprotein plays a critical role in receptor binding and viral fusion, thus, various monoclonal antibodies (mAbs) have been developed targeting the spike glycoprotein. However, the continuous emergence of new mutated variants makes the available mAbs less active. Our strategy was to generate mAbs to neutralize SARS-CoV-2 using hybridoma technology. A mouse immunoglobin (IgG), 6B1 mAb, was successfully generated, expressed, purified, and characterized. Despite unsuccessful attempts to form a complex between 6B1 Fab and the spike, the results indicate that 6B1 IgG has binding affinity towards the receptor binding domain (RBD) of the spike glycoprotein. Therefore, the complexing conditions must be optimized, and further evaluations are required, including neutralization activity and Cryo-electron microscopy (Cry-EM) to obtain the structural landscape of 6B1 mAb against the SARS-CoV-2 spike protein.