Anti-SARS-CoV-2 Antibody ELISA (S1RBD IgG)

Features

• It is intended for research use only.
• The total assay time is less than 3 hours.
• The kit detects IgG antibodies directed against SARS-CoV-2-S1 Receptor Binding Domain (RBD) in human serum or plasma.
• Assay format is 96 wells.
• The microtiter plater is coated with eukaryotic expressed recombinant SARS-CoV-2 S1RBD.
• Positive control serum and negative control serum are included with the kit.

Research topic

COVID-19

Summary

In December 2019 a novel coronavirus SARS-CoV-2 was identified in Wuhan, China and was announced as the causative agent for COVID-19 disease. The incubation period of the disease is 2-14 days. Symptoms of COVID-19 include fever, fatigue and cough, shortness of breath, muscle pain and tiredness. Most of the infected persons have a good prognosis, some of severe cases may have pneumonia, severe acute respiratory distress or even succumb to the disease.

The entry process of SARS-CoV-2 to the host cell is mediated by the envelope-embedded surface-located spike glycoprotein S. The protein is cleaved by host proteases into the S1 and S2 subunits, which are responsible for receptor recognition and membrane fusion, respectively. As target antigen of the assay the recombinant Receptor Binding Domain (RBD) of SARS-CoV-2 S1 spike protein, which binds the ACE2 receptor, is used. The use of RBD increases the specificity of the assay since the domain is identical with SARS-CoV but not with MERS-CoV for example. Antibodies directed against the RBD neutralize both virus strains SARS-CoV and SARS-CoV-2.

Up to now there are seven coronaviruses described which can infect humans. Two of them are alpha coronaviruses (229E, NL63) and five are beta coronaviruses (OC43, HKU1, MERS-CoV, SARS-CoV, SARS-CoV-2).

Mediagnost anti-SARS-CoV-2 ELISA E111 is a two-step enzyme-linked immunosorbent assay. Wells of a 96-well microtiter plate are coated with recombinant SARS-CoV-2 Spike protein S1 (RBD). After addition of human serum or plasma samples anti-S1 IgG antibodies from the sample bind to the immobilized antigen during a two hours incubation followed by several washing steps in order to remove unbound components. The bound anti-SARS-CoV-2 IgG antibodies are detected by incubation with HRP conjugated anti-human IgG for 30 minutes. Subsequently, an HRP substrate solution containing 3,3’,5,5’-Tetramethylbenzidine (TMB) is added resulting in the formation of a blue colour. The reaction is terminated by the addition of 0.2 M H2SO4 changing the blue colour into yellow signals which are measured by an absorbance microtiter plate reader at 450 nm. The extinction increases with the amount of the captured antibodies directed against SARS-CoV-2-S1 (RBD) from the infected person´s sera.