Previous work from this group of scientists, led by Tracy Hussell at Imperial College, London, showed that recovery from flu infection left mice unusually vulnerable to infection with pneumonia-causing bacteria. Components of these bacteria normally trigger receptors on immune cells in the lung. These signals result in the recruitment of other immune cells into the lung that help destroy the bugs. But in post-flu mice, these receptors were not triggered by bacteria and remained shut off for up to six months.
Shutting off bacteria-sensors may be the lung’s way of protecting itself from too much inflammation. If so, other inflammation inducers such as environmental allergens might also cause long-term immune suppression in the lungs.
Journal of Experimental Medicine