Test from Austria can determine corona immunity without antibodies
A MedUni Vienna research team has developed a blood test that provides information about immunity to the SARS-CoV-2 coronavirus within 48 hours. This test can be particularly relevant for vulnerable patient groups whose own antibody response is not meaningful.
The test also shows whether the immunity is due to a vaccination against SARS-CoV-2 or due to a survived infection. The data of the study were recently Allergy Magazine released.
“Many people cannot form antibodies – be it through immunosuppressive medication or chemotherapy. This test can now also be used to analyze cellular immunity, i.e. how well the T cells work against the virus. Until now, one was blind in one eye here,” explains immunologist and study leader Winfried Pickl (Med Uni Vienna).
To explain: The T-cells can look into the cell and constantly check it for their “identity card,” says Pickl. If something is wrong with the cell’s ID card, because the corona virus is multiplying in it, parts of the T cells are used as so-called killer cells – the other parts of the Z cells are helper cells for the antibodies (B cells).
This production of special messenger substances (so-called cytokines) is therefore decisive for the important antibody production, among other things.
For the first time, the test is being carried out in Austria as a quick routine: “At the moment it takes at least a week to carry out and evaluate these T-cell tests, and the tests can only be carried out in special laboratories. In contrast, our newly developed test IS carried out directly with a blood sample and can be evaluated after just 48 hours,” says Pickl.
The new test can be used from September at the Institute for Immunology at the Center for Pathophysiology, Infectious Diseases and
Immunology at the MedUni Vienna. It is not yet clear how much the test will cost. If the test is ordered at the AKH, the hospital pays for it.
Differentiation between vaccinated and recovered
In the course of analyzing the blood samples from patients who had recovered from COVID-19, the research team was not only able to detect large quantities of the two antiviral cytokines interleukin (IL)-2 and interferon-gamma using the peptide mixtures of S, M or NC proteins detect, but also identify the cytokine IL-13 as a marker for the highly specific T cell immune response to SARS-CoV-2.
IL-13 was previously known as a marker for allergic immune responses, but it also appears to play an important role in establishing a long-lasting antibody response. The use of the three different peptide mixtures also makes it possible to distinguish between people who have been vaccinated against the corona virus and patients who have contracted the corona virus.
The samples from recovered subjects respond with significant cytokine production to all three peptide mixtures, while the samples from vaccinated persons build up only the peptide mixture whose protein was induced by the vaccination (S-protein) and to which the vaccinated then also have cellular immunity.
The novel test therefore also makes it possible to detect a specific cellular immune response to SARS-CoV-2 in people who, for various reasons, are unable to develop a meaningful antibody response and thus confirm the success of a vaccination.
T-cell immunity is detectable longer than antibodies when infected
The study also examined the T cell response ten months after infection. A T-cell response that was just as strong as it was ten weeks after infection could be measured.
This is remarkable in that the antibody levels in the blood have already dropped significantly ten months after infection. This long-lived T-cell response should also protect against a severe course in the event of renewed infection with SARS-CoV-2 in the future. It has been shown that the cellular immune response of seriously ill people being treated in hospital is particularly strong.
The study in detail can be found here: Study online