This video explains how cells process virus proteins so that T cells can recognize infected cells. Additionally, it explains which type of T cell responds by targeting the infected cells for destruction and which T cells respond by helping other cells of the immune system to recognize that the virus is present and mount a response. [The video has no sound.]
Infected cells and cells of the innate immune system process the virus proteins. This also happens with the vaccines. The protein from the virus is processed into little fragments, called peptides. When those peptides are displayed on the surface of a cell and are recognized by the immune system, then they are considered antigens. Many different peptides can be made from a single virus protein. So, there are many possibilities for training the immune system’s T cells to recognize the infection even if mutations happen between the time a person is first exposed to the virus or vaccinated and the time the person is exposed again.
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Cite as: N. R. Gough, Killers and Helpers: How T Cells Recognize SARS-CoV-2. BioSerendipity (16 May 2021).