The SARS-CoV-2 Spike Protein Serological IgM ELISA Kit is a solid-phase ELISA that detects binding of human IgM to full-length ectodomain SARS-CoV-2 spike trimeric protein (S-protein). Trimeric spike protein has been coated onto microwells. After incubation with sample, human IgM specific for trimeric spike protein is captured on the plate. The wells are then washed to remove unbound material. Anti-Human IgM, HRP-linked antibody is then used to recognize the bound IgM. HRP substrate, TMB, is added to develop color. The magnitude of optical density for this developed color is proportional to the quantity of IgM specific for spike protein.

*Antibodies in this kit are custom formulations specific to kit.

The SARS-CoV-2 Spike Protein Serological IgM ELISA Kit detects endogenous levels of human IgM directed to full-length ectodomain SARS-CoV-2 spike trimeric protein (S-protein).

The cause of the COVID-19 pandemic is a novel and highly pathogenic coronavirus, termed SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). SARS-CoV-2 is a member of the Coronaviridae family of viruses (1). The genome of SARS-CoV-2 is similar to other coronaviruses, and is comprised of four key structural proteins: S, the spike protein, E, the envelope protein, M, the membrane protein, and N, the nucleocapsid protein (2). Coronavirus spike proteins are class I fusion proteins and harbor an ectodomain, a transmembrane domain, and an intracellular tail (3,4). The highly glycosylated ectodomain projects from the viral envelope surface and facilitates attachment and fusion with the host cell plasma membrane. The ectodomain can be further subdivided into host receptor-binding domain (RBD) (S1) and membrane-fusion (S2) subunits, which are produced upon proteolysis by host proteases at S1/S2 and S2’ sites. S1 and S2 subunits remain associated after cleavage and assemble into crown-like homotrimers (2,4). In humans, both SARS-CoV and SARS-CoV-2 spike proteins utilize the angiotensin-converting enzyme 2 (ACE2) protein as a receptor for cellular entry (5-7). Spike protein subunits represent a key antigenic feature of coronavirus virions, and therefore represent an important target of vaccines, novel therapeutic antibodies, and small-molecule inhibitors (8,9).