Memories help people avoid making the same mistake twice. Cellular memory, in the form of immune cells, does a similar service. B cells and T cells can hang out in tissue like the lungs after an infection, just in case that particular bad actor comes back. It’s called resident memory and in the case of immunity against the flu, it’s good to have plenty of it.

Using a mouse model, Mayo immunologist Jie Sun, Ph.D., and colleagues have discovered a new “coordinator” for B and T cells, called T resident helper cells. These cells help develop B and T cell memory responses in the respiratory system  after a bout with the flu.

According to the researchers in their article in Science Immunology, immune resident memory lives in mucosal tissue and is present to spur on B and T cell protective responses whenever a virus appears. The memory helps jump start the defense, with a plan of attack formulated from previous experience.

Why is this important? The authors say lung protective responses to the flu are rather short lived and that trait is a problem when one is trying to develop a vaccine. Knowing how to engage these T resident helper cells may aid scientists when they design future influenza vaccines, especially the development of a universal flu vaccine.