This is a T-cell and therefore you cannot test

The body's immune cells - so-called T-cells - both strengthen the production of antibodies and attack already infected cells. This shows new research. The fact that T cells kill corona infected cells may be because the infected person has had similar cold viruses in the past. 

- It is believed that this is because the T-cells have previously been exposed to some other coronavirus and now recognize parts of the new coronavirus, says Gustaf Christoffersson immunologist at the Department of Medical Cell Biology at Uppsala University. 

Researchers now hope that the new studies will lead to a more effective vaccine. 

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