'Memory when suffering from a common cold' may be effective for new coronavirus infection

There is a possibility that the immune system of a person who has a ``cold coronavirus'' that causes a common cold can recognize a new coronavirus (SARS-CoV-2) that causes a new coronavirus infection (COVID-19) But it turned out by a new experiment. It is hoped that this discovery will help understand why some people may suffer from COVID-19 with mild illness, or may end up asymptomatic without losing their physical condition.

Selective and cross-reactive SARS-CoV-2 T cell epitopes in unexposed humans | Science
https://science.sciencemag.org/content/early/2020/08/04/science.abd3871

Exposure to common cold coronaviruses can teach the immune system to recognize SARS-CoV-2: Researchers caution: It is too soon to say whether pre-existing immune cell memory affects COVID-19 clinical outcomes --ScienceDaily
https://www.sciencedaily.com/releases/2020/08/200804100219.htm

Although COVID-19 is an infectious disease that causes death when it becomes severe, there are many COVID-19 infected people who remain mild and asymptomatic who do not feel ill at all. Previous studies have shown that older people and people with chronic illness are more likely to become severe, but it is difficult to explain why such inter-individual symptoms differ so much. ..

Why is new coronavirus infection severe in only some people? -GIGAZINE

Therefore, the research team of Alessandro Sette, an immunologist at the La Jolla Immunological Institute in California, focused on T cells , a type of immune cell. There are multiple types of T cells, one of which is the 'memory T cell' that survives in the body for a long time and retains the memory of the pathogen, and quickly responds to the same infectious disease next time. To do. This mechanism is called immune memory.

According to Sette et al., an experiment in which T cells of a patient recovered from COVID-19 are exposed to a fragment of SARS-CoV-2, 'the T cells of a person with COVID-19 can respond to SARS-CoV-2' I confirmed. From this, it was found that people with COVID-19 are more likely to acquire immunity to SARS-CoV-2.

What kind of cells are 'T cells' that are the key to the possibility of acquiring immunity to the new coronavirus? -GIGAZINE

In the above experiment, 'T cells of humans recovered from COVID-19' were used, but in a new study published this time, 'SVs before the discovery of COVID-19 3 We exposed human T cells collected between March and March 2018 to SARS-CoV-2 and fragments of the human coronavirus (cold coronavirus) that cause the common cold.

As a result, it was found that even those who have never had COVID-19 produce memory T cells that show equivalent responses to SARS-CoV-2 and four cold coronaviruses.

``I knew that the immune system could respond to SARS-CoV-2, but this experiment shows that memory T cells capture similar features between cold coronavirus and SARS-CoV-2,'' said Sette. I got very strong and direct evidence that I can do that.'

``Our work showed that T-cell memory of the common cold coronavirus captured the precise molecular structure of the virus, SARS-CoV-2,'' said Daniella Wyckoff, co-author of the paper. It has been shown to be able to cause a cross-reactivity to, which explains why some people with COVID-19 become more severe while others have milder symptoms. May be useful.'

In addition, this study, which exposed T cells to fragments of SARS-CoV-2, revealed that T cells can recognize the various types of proteins that SARS-CoV-2 possesses. Many COVID-19 vaccines currently under development target the substance called the spike protein of SARS-CoV-2, but the protein of SARS-CoV-2 that human T cells can recognize is spiked. Since it has been shown that it is not limited to proteins, it is expected that vaccines that approach SARS-CoV-2 in a wider range of ways will be developed in the future.