The test uses the interaction between viral protein-receptor protein to mimic the virus infection of a live cell, which is monitored by a chromogenic reaction.
When there are neutralizing antibodies in the patient sera, they will block the specific protein-protein interaction and hence reducing the chromogenic reaction, mimicking the virus neutralization process.
Most COVID-19 antibody test kits in the market evaluate the ability of a patient to generate antibodies bind virus, such as IgG, IgM, or total antibody, but they do not tell whether such antibodies can neutralize the virus and break virus life cycle, which is essential for a person’s acquired immunity against the pathogen. Our kit detects the antibodies that have blocking/neutralization function. Therefore, it is a better measure of potential resilience to re-infection.
Traditionally, the presence of neutralizing antibodies are detected by virus neutralization test(VNT). Conventional virus neutralization tests require live viruses and cells, biosafety containment facilities, highly skilled operators, are less sensitive, and take days to obtain results. Our cPass™ test does not involve live virus and cells and can be used in any lab, except the test sample itself is infectious and need biosafety level 2 or 3 (BSL2, BSL3) labs. The operation steps are much more straightforward and only take 1 hr to run.
The standard virus neutralization test (VNT) uses live virus to infect human cells. Anything that can inhibit the infection can be recognized as a neutralization agent. This method has been the gold standard. However, the process is tedious (takes days) and requires using high level safety lab facility (biosafety level 3). Therefore, the assay is expensive and cannot be widely used.
Another approach is pseudovirus neutralization test, it is specific and can be performed in BSL2 labs. However, it is still dependent on live cells and virus and is hard to commercialize.
Our kit measures protein-protein interaction which does not require live cells or virus. Our kit can be used in any laboratories unless you are handling health hazardous samples, which requires BSL2 or BSL3 based on local regulation. It can also amenable to automation.
When using as serology test on patients, if the cPass™ test gives a positive result, it means the person most likely has been infected by the virus in the past, indicating potential immunity against the virus. With this serology test, large amount of data can be provided for epidemiologic study.
In the society or community, this is the most practical way to evaluate the level of “herd immunity”.
It can be used to test whether an animal or a pet has been infected by COVID-19 virus. In zoology studies, this can be used to find out the animal intermediate host of COVID-19.
In vaccine development, it can be used to evaluate the ability of vaccines to generate such antibodies in vaccine immunized population, and to measure how long the neutralizing antibodies exist.
In clinical therapeutics, this kit can be used to identify which donor has the functional neutralization antibodies, and with confirmed negative qRT-PCR that shows viral clearance, the individuals might be a qualified volunteer to donate serum for passive therapeutics to save seriously ill patients.
This kit can also be used to screen therapeutic antibodies, which are engineered to block the interaction between RBD and ACE2.
As our kit is species-independent, customers can use our kit to screen antibodies derived from any host, such as mouse, rabbit, human, or llama.
The cPass™ kit is a serology test that checks the neutralizing antibody against SARS-Cov-2 in response to infection. It should not be used to diagnose acute SARS-CoV-2 infection, as the antibodies could not be generated in a short time period.
On the other hand, an individual with past infection but already have virus clearance may still have neutralizing antibody as acquired immunity.
Diagnostic tests are molecular tests that mainly check genetic material from the virus itself, usually by Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR), to diagnose active infections through nasal swab, throat swab, saliva, etc.