COVID-19 Neutralizing Antibody Test Kit
On July 4, 2020, JOYSBIO released the first COVID-19 Neutralizing Antibody Rapid Test Kit (Lateral Flow Cassette) for the detection of SARS-COV-2 Neutralizing Antibodies (NAb), which can be used to determine the Immunity status after infection or vaccination.
As in many infectious diseases, neutralizing antibodies can help inhibit the replication of SARS-CoV-2, which means that the level of neutralizing antibodies correlates with immunity from future SARS-CoV-2 infections. Rapid detection of neutralizing antibodies can help with vaccine development, plasma therapy, and the study of immunology.
Characteristics:
- Rapid immunity assessment in 25 minutes.
- Tested by clinical evaluation with subjects who received the Pfizer-BioNTech vaccine.
- Compatible with serum, plasma, whole blood and fingertip blood.
- Compatible with optical reading device for POC.
What are neutralizing antibodies?
Not all antibodies are neutralizing. Non-neutralizing antibodies, or binding antibodies, can bind to viral antigens but do not block viral infection. Binding antibodies can tag the viral antigen to elicit immune responses, but the presence of binding antibodies does not reflect the level of immunity. Neutralizing antibodies (NAb) are antibodies that not only bind to viral antigens but also block viral infection. The presence of NAb can be used to assess immunity status after infection or vaccination.
Intended use of the Rapid Neutralizing Antibody Test
The 2019 novel coronavirus (SARS-CoV-2) has several structural proteins, including spike (S), envelope (E), membrane (M), and nucleocapsid (N). Protein S contains a receptor-binding domain (RBD), which can recognize the cell-surface receptor, angiotensin-converting enzyme-2 (ACE2). In a recent study, neutralizing antibody (NAb) can block the interaction between the receptor-binding domain (RBD) of the novel coronavirus spike protein with the cell-surface receptor ACE2.
The level of NAb can therefore be used to test a patient’s immunity against future SARS-CoV-2 infection. This COVID-19 neutralizing antibody lateral flow assay rapidly detects any antibodies that can neutralize the RBD-ACE2 interaction. Researchers have been using the traditional viral neutralization assay to test for SARS-CoV-2 neutralizing antibodies and there are several ELISA-based neutralizing antibody test kits available on the market since May 2020.
However, testing COVID-19 neutralization or ELISA requires complex laboratory setups, and is time-consuming, despite increased sensitivity and specificity. The JOYSBIO Surrogate Neutralizing Antibody Rapid Test Cassette provides an easy way to perform preliminary NAb screening to estimate patients’ immunity to novel coronavirus infection.
COVID-19 NAb Rapid Test Principle
JOYSBIO’s COVID-19 Neutralizing Antibody Test Kit is a lateral flow assay for the rapid detection of NAb, which can mimic the virus neutralization process. This lateral flow assay contains two key components: the recombinant SARS-CoV-2 RBD fragment and chick IgY, labelled with colloidal gold, are like tracers; and the human ACE2 receptor protein (hACE2) and the goat anti-chicken IgY antibody, coated with a cellulose nitrate membrane. The protein-protein interaction between RBD and hACE2 can be blocked if the test samples contain a certain level of neutralizing antibodies against SARS-CoV-2.
When samples are added to the sample pad, neutralizing antibodies present in the sample will bind to the RBD-labeled colloidal gold and block the protein-protein interaction between RBD and hACE2. Unbound RBD-labeled colloidal gold, as well as any RBD-labeled colloidal gold bound to the non-neutralizing antibody, will be captured on the test line. Colloidal gold-labelled chicken IgY antibody binds to goat anti-chicken IgY antibody coated with a coloured band (line C), which acts as a procedural quality control line.
COVID-19 Neutralizing Antibody Rapid Test Operation Procedure
JOYSBIO COVID-19 Neutralizing Antibody Test Procedure JOYSBIO COVID-19 Neutralizing Antibody Test Procedure
Step 1:
Wipe to clean the puncture site on your finger with the alcohol pad.
Step 2:
Remove the cap from the safety lancet, press the lancet firmly against the puncture site.
Step 3:
Use the disposable pipette to draw blood from the puncture site.
Step 4:
Add one (1) drop (20 µL) of blood from a disposable pipette to the sample well in the test cassette.
Step 5
Add three (3) drops (100µL) of dilution buffer from the buffer bottle to the buffer well in the test cassette.
Step 6:
Start the timer. Read the test results in 25-30 minutes. Do not read the results after 30 minutes.
Interpretation of results
Without a cassette reading device, test results can be visually interpreted:
Positive IgG and Negative Neutralizing Antibody: Three lines appear. A coloured line appears in the region of the control line (C), a coloured line appears in the region of the IgG test line (1), and a coloured line appears in the region of the IgG test line neutralizing antibodies (2) that is darker or the same as the Cline.
Positive IgG and Positive Neutralizing Antibody: A coloured line appears in the region of the control line (C), a coloured line appears in the region of the IgG test line (1), and the colour appears in the region of the Neutralizing antibody test line (2) is clearer than Cline. When the region of the neutralizing antibody test line (2) does not show a visible line, it represents a high level of neutralizing antibodies.
NEGATIVE: Two lines appear. A coloured line appears in the region of the control line (C), and a coloured line appears in the region of the neutralizing antibody test line (2) that is darker or the same as the Cline.
INVALID: The control line does not appear.