What is T-Cell Immunity and how does it relate to COVID?

What is T-Cell Immunity?

T-cells are one type of cell that makes up your immune system. T-cells fight infections by hunting down other cells that are infected and destroying them. This prevents the infection from continuing to spread to nearby cells. T-cells are also part of immune memory, which allows your immune system to remember past infections.

Recent studies suggest that people who have recovered from COVID-19 have T-cells that hunt and kill cells infected with the novel coronavirus that causes COVID. This was true even in some people who did not produce antibodies to the virus. 

More surprisingly, T-cells from some people who had no known exposure to COVID-19 stil recognized the novel coronavirus. T-cells that recognized the virus were even found in blood samples taken before the pandemic (2015-2018). Scientists think that this is most likely due to exposure to other coronaviruses.

What does all this mean?

  • People who have recovered from COVID-19 may have some protection against the virus even if they don’t have antibodies.
  • Potential vaccines might stimulate both an antibody response and T-cell response, which could make a vaccine more effective.
  • Prior exposure to other coronaviruses, which cause thec common cold,  might “prime” the immune system to recognize the virus that causes COVID. We don’t know if this has any effect on how sick people get.

We don’t yet know what T-cell immunity to COVID-19 means for the spread of the virus or how it might interact with other immune responses. Learning more about how the immune system fights COVID can help scientists make better vaccines and more accurate predictions about how COVID will continue spreading.

Last update: August 11, 2020, 9:00 pm ET

Science review: GSN, JAB