How T cells and antibodies team up against viruses

When an invader like the COVID-19 virus or influenza virus gets in your body, it has one mission: to replicate itself and infect as many of your cells as possible. Luckily, your immune system is ready to fight back.

T cells — or T lymphocytes — are key players in defending your body against invaders, called pathogens, like COVID-19 and influenza. T cells are white blood cells. They work with antibodies, which are proteins your body makes to fight pathogens.

When a pathogen gets in, your body starts making more T cells and antibodies to fight it. Antibodies might get more attention for their role against viruses, but T cells are just as important.

Pathogens have unique antigens on their surfaces. These antigens tell the T cells what the pathogen is, so they can attack.

T cells are programmed to recognize a specific antigen. When T cells find an antigen they recognize, they can easily grab onto it. This prevents the virus from infecting healthy cells.

Why vaccines are important

If it's your body's first time seeing a virus, it can take a while to make the necessary antibodies and T cells to fight it.

That's where vaccines come in. They give your body a head start in making T cells and antibodies. Then if you become infected, your immune system is ready to go. It already knows how to identify and destroy the pathogen.

After an infection is cleared, most T cells retreat. But some continue to circulate around your body looking for antigens in case they need to activate again. That's reassuring news for the body's long-term ability to fight the virus.

This information is adapted from a Mayo Clinic Health Letter article. For more Mayo Clinic Health Letter content, visit the Mayo Clinic Press website.