T cells, or T lymphocytes, protect against COVID-19 even in the absence of antibodies. They are also present in people who have had the infection asymptomatically and who have not formed antibodies. In addition, scientists have found that T cells that "recognize" the coronavirus are also present in blood samples taken before meeting with covid.
Researchers explain this phenomenon by cross-immunity caused by previously transferred other viral infections, which are similar to COVID-19 from the point of view of the immune system. There are also several scientific works that have proven that some people have not only acquired, but also the so-called innate immunity to coronavirus, based on cell memory. It is not yet possible to pass a T-cell test for immunity to covid - there are no such registered systems in Russia. Daria Goryakina, Deputy Director General of the Helix Laboratory Service, comments.
Daria Goryakina Deputy Director General of Helix Laboratory Service “Several suppliers have developed or are planning to develop this test. In particular, Helix is currently testing several test system reagents, and we plan to launch a T-cell test in January. Now the so-called T-Spot test is widely used - this is a test for tuberculosis. The COVID-19 T-cell test will have exactly the same procedure as the T-Spot. Another test is performed for borreliosis, Lyme disease - absolutely the same technology. It will cost more than antibody tests. Testing for antibodies to COVID-19 starts at 650 rubles. It will cost, I think, about six thousand. While the pricing is not clear, while we do not understand exactly the cost of the reagent."
The high cost in "Helix" is also explained by the fact that the test requires a lot of manual work and it takes several hours to get the result. In Russia, specialists from the National Medical Research Center of Hematology under the Ministry of Health are also developing a test for T-cell immunity for covid. They noted that the result is still measured in days and, at best, their test will appear at the end of winter. The head of the transplant immunology laboratory of the center Grigory Efimov comments.
- The test for clinical use is not yet used. It is in the final stages of development. Then clinical trials, then, we hope, it will be registered, and we expect to apply for registration in February.
- How difficult is it to do?
- It takes several days. It's harder than antibodies. Therefore, it will be significantly more expensive. Additional equipment is required, and as living cells are examined, handling is required to keep them alive during the experiment.
- Now they are talking about the mutation of the coronavirus. How much can the presence of this immunity protect a person?
- From what we now know, it does not seem that the virus will be able to escape from T-cell immunity by mutation. According to the rate of those mutations that we observe, according to their nature, there is no indication of this now.
Scientists cannot yet answer the question of whether a vaccine is needed at all when there is T-cell immunity. More research is required. So far, there is little research from Oxford Immunotech. She is developing a test system similar to the Russian one. The study found that people who had T lymphocytes did not get infections.
Also, Adaptive Biotechnologies in the United States is developing a test for determining T-cell immunity. Which test will be more perfect remains to be seen. In the meantime, according to scientists, the most reliable immune response is still a vaccine.
At the end of November, Moscow Mayor Sergei Sobyanin said that almost half of Moscow's population was “theoretically” protected from the coronavirus. According to him, the studies carried out in the capital show that about 50% of the population already have an immune response, T-cell immunity, and antibodies.
