Cayman Chemical SARS-CoV-2 Neutralizing Antibody Detection ELISA Kit

Cayman Chemical’s SARS-CoV-2 Neutralizing Antibody Detection ELISA Kit is a competitive assay that can be used for qualitative and/or semi-quantitative measurement of neutralising antibodies in human plasma and serum. When using the reference neutralising antibody provided in the kit, the assay has a range of 7.81–1000 ng/mL with a midpoint of approximately 107 ng/mL (50% B/B₀) and a sensitivity (80% B/B₀) of approximately 41 ng/mL.

The RUO kit enables semi-quantitative identification of neutralising antibodies against the novel coronavirus that causes COVID-19. Starting ~4–10 days after symptom onset, SARS-CoV-2 infection can result in the production of neutralising antibodies that bind to the viral spike protein receptor binding domain (RBD) on the S1 subunit and prevent its interaction with the human ACE2 receptor, preventing further viral entry and infection. By screening for the circulating antibodies that interrupt this binding, investigators will be able to study antibody response and recovery from infection.

The competitive ELISA includes a SARS-CoV-2 neutralising antibody as a standard that was carefully tested to ensure its interference with the ACE2 protein for binding sites on the SARS-CoV-2 spike S1 RBD. Robust and easy to use, the assay can be completed in <4 h using a plate-based, colorimetric (450 nm) readout. The kit was validated using plasma from volunteers that tested positive in a PCR test for COVID-19. The semi-quantitative design is claimed to be the first of its kind for SARS-CoV-2 seropositivity testing and provides a consistent reference point for neutralising antibody levels not readily available with standard serological assays.