(HealthDayNews) -- Your blood may have a better memory than your brain.
When you're exposed to a virus, your immune system makes antibodies that help protect against infection.
But your T-cells, which are a group of white blood cells, also learn the characteristics of the virus and help protect you.
Some of these T-cells have a very good memory. According to the Journal of Clinical Investigation, research shows that T-cells were protecting against a specific virus for as long as 13 years after a single exposure.