T Cell Immunity?

COVID-101 For Kids

Maybe you’ve heard the word immunity a lot this year. Having immunity, or “being immune”, means your body is able to fight off specific diseases by recognizing it quickly and eliminating pieces of disease.

In school you may learn that being immune relies on your body making antibodies to keep you safe. Antibodies are little recognition machines (like the fingerprint sensor on new phones or facial recognition software that identifies faces in pictures) and they alert the white blood cells of your immune system to act! Being exposed to a disease once (either through becoming sick or getting a vaccination) usually makes your body produce lots and lots of antibodies to protect you from ever getting that disease again. The cell that makes antibodies is a white blood cell called a B cell.

Knowing this, doctors can check if you’re protected against a certain disease or not by testing some of your blood to look for those specific antibodies. If you have enough antibodies, you’re considered immune; if not, you could still potentially get sick.

But, we are learning it isn’t so simple. Some people are protected from a disease even if they don’t have antibodies, and scientists know this is because of another special white blood cell in your immune system: T cells. T cells fight infections by hunting down and destroying other cells that have become infected, and T cells are usually activated by antibodies.

Recent studies suggest that people who have recovered from COVID-19 have T cells that hunt and kill other cells infected with the novel coronavirus. This was true even in some people who did not produce antibodies to the virus. Even more exciting is that some people have T-cells which recognize bits of coronavirus even if those people have never been exposed to the new virus (even blood samples taken five years ago!) This means those T cells might have been exposed to another similar corona virus and still have the ability to protect us from getting COVID-19. This different type of protection is called “T Cell Immunity”.

What does it all mean? It’s an exciting scientific finding showing how our immune system is very complicated and good at protecting us. It’s possible this disease leads to immunity through T cells as well as immunity through antibodies. However, if you receive an antibody test and you have no antibodies for the novel coronavirus it is most probable that you are still able to catch the virus and become sick. Don’t rely on t-cells alone to protect you! It is also important that once a safe vaccine is released, after rigorous testing, that people get vaccinated to protect ourselves and each other from catching the virus.

Author: Rob Frawley PhD
Original COVID-101 article by Brad Kern PhD