Methodology
- Serology
- OAntibody assay
- Antibody detection
- Dynex DSX automated ELISA platform
- Tru-Immune SARS-CoV-2 Neutralizing Antibody ELISA test
Semi-quantitative results are reported with the following ranges of percent inhibition:
Negative <20% Inhibition
Positive 20-40% Inhibition
Positive 40-60% Inhibition
Positive 60-80% Inhibition
Positive >80% Inhibition
Not provided
The Tru-Immune SARS-CoV-2 Neutralizing Antibody ELISA Test is a blocking ELISA detection tool, which mimics the virus neutralization process. The kit contains two key components: Horseradish peroxidase (HRP) conjugated recombinant SARS-CoV-2 RBD fragment (HRP-RBD) and the human ACE2 receptor protein (hACE2). The protein-protein interaction between HRP-RBD and hACE2 can be blocked by neutralizing antibodies against SARS-CoV-2 RBD.
First, the samples and controls are pre-incubated with the HRP-RBD to allow the binding of the circulating neutralization antibodies to HRP-RBD. The mixture is then added to the capture plate which is pre-coated with the hACE2 protein. The unbound HRP-RBD as well as any HRP-RBD bound to non-neutralizing antibody will be captured on the plate, while the circulating neutralization antibodies-HRP-RBD complexes remain in the supernatant and get removed during washing. After washing steps, TMB solution is added, making the color blue. By adding Stop Solution, the reaction is quenched, and the color turns yellow. This final solution can be read at 450 nm in a microtiter plate reader. The absorbance of the sample is inversely dependent on the titer of the anti-SARS-CoV-2 neutralizing antibodies.
Citations- A SARS-CoV-2 surrogate virus neutralization test based on antibody-mediated blockage of ACE2-spike protein-protein interaction. - PubMed ID:
32704169
Assessment of the Tru-Immune SARS-CoV-2 Neutralizing Antibody ELISA test results should be performed after the positive and negative controls have been examined and determined to be valid and acceptable. If the controls are not valid, the patient results cannot be interpreted. The results are interpreted using the following steps:
Read and record the absorbance values in the microtiter plate reader at 450 nm.
Convert the absorbance values to percent inhibition based on the following equation:
"Inhibition = " ("1 - " "OD value of Sample" /"OD value of Negative Control" )" × 100%"
All Inhibition values ≥ 20% are reported as positive and all Inhibition values < 20% are reported as negative.
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