Application Note: Multiplexed SARS-CoV-2 Serological Assay Using Advanced Flow Cytometry

The coronavirus disease 2019 (COVID-19) pandemic has had a profound impact on human life. The causative agent of COVID-19 is the betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which continues to be a global public health threat.

Upon infection, SARS-CoV-2 initiates entry into target cells through the interaction of the receptor binding domain (RBD) on the S1 subunit of its envelope Spike glycoprotein with the angiotensin-converting enzyme 2 (ACE2) on human cells. This interaction then induces a conformational change in the S2 subunit of the Spike glycoprotein that results in virus-host cell membrane fusion and viral entry.

Antibodies directed against the RBD of the SARS-CoV-2 Spike protein can effectively neutralize the virus by blocking virus interaction and entry into host cells. Production of these neutralizing anti-Spike RBD antibodies is also an important factor in the protective immunity induced by current COVID-19 vaccines. Several isotypes of neutralizing anti-Spike RBD antibodies (IgG, IgM and IgA), have been identified in both COVID19 patients and in vaccine recipients.