Immunity: automatic controls of inflammation (Introduction)

by David Turell , Thursday, October 18, 2018, 19:48 (2014 days ago) @ David Turell

New automatic controls over neutrophils are described:

https://medicalxpress.com/news/2018-10-mechanism-inflammation.html

"The first immune cells to arrive at the infection or inflammation site are the neutrophils, and these cells are tasked with eliminating the source of the problem. However, neutrophils are very destructive and not only act on the infecting pathogen, but also damage the infected tissue. This tissue damage caused by our own defense system is known as immunopathology. It is therefore important to understand how our immune system can control the neutrophil inflammatory response to prevent it damaging our own tissues. The current study shows that tissue infiltration by neutrophils is controlled by dendritic cells. These cells are more well known for the essential role they play in directing the specific responses of T lymphocytes. The new study shows that dendritic-cell regulation of neutrophil infiltration helps to avoid excessive tissue injury."'

"'Dendritic cells attract neutrophils to the inflammatory focus by releasing factors such as the chemokine Mip-2. At the same time, these cells also express the surface receptor DNGR-1. This cell-surface molecule detects tissue injury by identifying cell components that become accessible only when the cell is damaged or 'broken'. When DNGR-1 detects damaged tissue, it reduces the capacity of the dendritic cell to produce Mip-2, thus limiting neutrophil infiltration to the damaged organ. This mechanism prevents what could otherwise be a life-threatening expansion of tissue injury."

"Paula Saz, the other co-first author on the study, emphasized the importance of understanding immune system regulation, both as a positive response, favoring the fight against infection or cancer and promoting tissue repair, and in its negative manifestations that can cause excessive inflammatory injury during infection, as well as allergic reactions or major autoimmune diseases. "This balance always exists in the immune system, and learning how to control it is the key to the fight against many diseases with an immune component.'"

Comment: All of these reactions and controls are automatic molecular effects. one molecule acting on another in a series. It is important that the inflammatory reaction is confined to the infected area only since it is damaging to normal uninfected tissue. It is like the clotting mechanism which is controlled to the damaged vessel or tissue. It cannot be allowed to clot the entire circulatory tree. How is this kind of control developed by chance? Obviously it cannot be and requires careful design.