Alarm signal: intestinal cells create it as a chain reaction when parasites invade

Intestinal cells create an alarm when parasites invade

The scientists from the School of Veterinary Medicine traced a unique chain reaction. It occurs in the cells lining the intestines, and it turns on the immune system when parasites enter the body. In order to begin the fight against infection, the body must conclude that an alien invasion has occurred. The affected tissue begins to send certain signals for this at the early stages of the spread of pathogens.

These tips are essential when it is needed to stop the inflammatory process resulting from active immunity. The specialists at the University of Pennsylvania studied infections caused by the Cryptosporidium parasite.

They decided to find the very signals that are emitted by the affected part of the tissue. But they managed to trace them not to the immune cell, but to the epithelial cells that line the intestines. This is where the parasite will settle.

The cells known as enterocytes take nutrients from the intestine, alerting the body to molecular dangers through a specific NLRP6 receptor, which is a component of the so-called inflammasome. Professor Bori Stripen compares inflammasomes to an alarm system in a house. It picks up the first signals and sends a call for help, this is how the receptor works.

But typically, the scientists focus on immune cells such as macrophages and dendritic cells. It is generally accepted that they are the first to detect foreign components. But the cells of the intestinal epithelium had never been like that. In this case, in the course of a new study, it turned out that they play a key role when triggering an immune response.

According to the experts, their observations prove that epithelial cells are the first to help the immune system to recognize pathogens.

Reference: 28 December 2020, Proceedings of National Academy of Sciences.