A good night’s sleep not only strengthens your memory but also strengthens the response-memory of your immune system when it comes to killing bad bacteria and viruses as they enter your body, new research reveals. The immune system “remembers” an encounter with a bacteria or virus by collecting fragments from the bug to create memory T cells, which last for months or years and help the body recognise a previous infection and quickly respond. These memory T cells appear to abstract “gist information” about the pathogens. The selection of “gist information” allows memory T cells to detect new pathogens that are similar, but not identical, to previously encountered bacteria or viruses. Now, German researchers propose that deep sleep may also strengthen immunological memories of previously encountered pathogens. “The idea that long-term memory formation is a function of sleep effective in all organismic systems is entirely new in our view,” said senior study author Jan Born from University of Tuebingen. “We consider our approach toward a unifying concept of biological long-term memory formation, in which sleep plays a critical role, a new development in sleep research and memory research,” he said. Studies in humans have shown that long-term increases in memory T cells are associated with deep slow-wave sleep on the nights after vaccination. Taken together, the findings support the view that sound sleep contributes to the formation of long-term memories which lead to adaptive behavioural and immunological responses. The obvious implication is that sleep deprivation could put your body at risk. “If we didn’t sleep, then the immune system might focus on the wrong parts of the pathogen,” Born added.