Your immune system’s ‘memory’ T cells keep track of the viruses they have seen before. This immune cell memory gives the cells a headstart in recognizing and fighting off repeat invaders.
Now, a new study led by scientists at La Jolla Institute for Immunology (LJI) shows that memory helper T cells that recognize common cold coronaviruses also recognize matching sites on SARS-CoV-2, the virus that causes COVID-19.
The research, published Aug. 4, 2020 in Science, may explain why some people have milder COVID-19 cases than others—though the researchers emphasize that this is speculation and much more data is needed.
“We have now proven that, in some people, pre-existing T cell memory against common cold coronaviruses can cross-recognize SARS-CoV-2, down to the exact molecular structures,” says LJI Research Assistant Professor Daniela Weiskopf, Ph.D., who co-led the new study with LJI Professor Alessandro Sette, Dr. Biol. Sci. “This could help explain why some people show milder symptoms of disease while others get severely sick.”
“Immune reactivity may translate to different degrees of protection,” adds Sette. “Having a strong T cell response, or a better T cell response may give you the opportunity to mount a much quicker and stronger response.”
The new work builds on a recent Cell paper from the Sette Lab and the lab of LJI Professor Shane Crotty, Ph.D., which showed that 40 to 60 percent of people never exposed to SARS-CoV-2 had T cells that reacted to the virus. Their immune systems recognized fragments of the…
