Scientists have discovered that the same specialised immune cells that patrol the body and spot infections also trigger the expansion of immune organs called lymph nodes.
The immune system defends the body from infections and can also spot and destroy cancer cells. Lymph nodes are at the heart of this response, but until now it has never been explained how they expand during disease.
The researchers - at Cancer Research UK's London Research Institute (LRI; now part of the Francis Crick Institute) - found that when a type of immune cell called a dendritic cells recognises a threat, it makes a molecule called CLEC-2 that tells the scaffold cells within the lymph nodes to stretch out and expand. This allows an influx of disease fighting cells. It has long been known that these same dendritic cells patrol the body searching for threats and call for reinforcements to tackle them.
Dr Caetano Reis e Sousa of LRI, said: "This important research helps us unravel how the immune system works and its role in diseases. We've shown for the first time the dual role of dendritic cells in responding to infection - both recognising that there is a threat in the body but also telling the lymph nodes to stretch out. This expansion of the lymph nodes, the command centres of the immune system, gives more room for immune cells to gather and launch their attack against infections and cancer."
Dr Sophie Acton, a Henry Wellcome Postdoctoral Fellow at University College London visiting Dr Reis e Sousa's lab, said: "The more we understand about how the immune system recognises and responds to disease the better we can start to prevent it. We need to now see if this is the same mechanism that is used in the immune system's response to cancer and how we can exploit it to fight the disease."
The paper, Dendritic cells control fibroblastic reticular network tension and lymph node expansion, is published inNature.
