SARS-CoV-2 (Spike RBD) IgG Serological ELISA Kit

Coronaviruses (CoVs) are enveloped non-segmented positive-sense RNA virus for human and vertebrates. They are classified into four types, alpha-CoV, beta-CoV, gamma-CoV, and delta-CoV. They can infect respiratory, gastrointestinal, hepatic, and central nervous system of human and many other wild animals. The family Coronaviridae constantly circulate in the human population and mainly cause mild respiratory diseases. In December 2019, a new severe acute respiratory syndrome beta-coronavirus called SARS-CoV-2 (or 2019-nCoV) has emerged, which causes an epidemic of acute respiratory syndrome (called coronavirus human disease 2019 or COVID-19).SARS-CoV-2 virus contains 4 structural proteins, spike (S), envelope (E), membrane (M) and nucleocapsid. The spike protein (S) is a transmembrane protein, composed of the S1 subunit and S2 subunit. The S1 subunit contains a receptor binding domain (RBD), which binds to the cell surface receptor Angiotensin-Converting Enzyme 2 (ACE2) present at the surface of epithelial cells, causing infection of human respiratory cells. During an infection, IgM antibody appears first, followed by IgA on mucosal surfaces or IgG in the serum. The spike (S), mainly the RBD domain and the nucleocapsid (N) are the main immunogens of Coronavirus leading to antibody answer. This assay is an indirect ELISA assay (based on Spike (RBD) coated protein) for qualitative measurement of human anti-SARS-CoV-2 IgG in serum and plasma. In this assay, a second plate (antigen non-coated Background Plate) is provided to measure the amount of IgG antibodies non-specifically bound to the well. To measure presence of anti-anti-SARS-CoV-2 human IgG antibodies in serum or plasma, net sample optical densities (Net OD) are calculated by subtracting each sample Background Plate OD from the Spike (SARS-CoV-2) antigen plate (Spike Plate) OD.