The immune system is fast when it comes to fighting viruses, bacteria and other pathogens. But it also has to know when not to attack – for example, harmless substances such as pollen or house dust, which otherwise trigger allergic reactions. Regulatory T cells (Tregs) in the lymph nodes play a key role here, suppressing excessive or misdirected immune responses there.
Researchers at the University of WĂĽrzburg (JMU) and the University Hospital RWTH Aachen have now observed a previously unknown behaviour of these cells: “Until now, it was assumed that Tregs circulate between lymph nodes throughout the body to coordinate immune responses,” says Dr. Milas Ugur, head of the study at the Institute for Systems Immunology at JMU. “However, we were able to show that there are also resident Tregs that remain in certain lymph nodes for a long time. Some even nest there for several months!”
Tregs store information about past immune responses
This observation was made possible by a technique called “photoconversion”. It allows cells to be marked by light – with a special torch, as it were – and their changes in position to be observed over longer periods of time.
The result: each lymph node contains a unique set of resident Tregs that map past immune responses. There they function as the local memory banks of the immune system.”
Prof. Wolfgang KastenmĂĽller, Chair of Systems Immunology I at JMU
Tregs play an important role in allergies and autoimmune diseases. “We now know that