Immunity system complexity: handling gut pathogens (Introduction)

by David Turell , Friday, May 24, 2019, 21:10 (2009 days ago) @ David Turell

Immunity varies in the gut, depending on the level:

https://medicalxpress.com/news/2019-05-reveals-gut-segments-function.html

"As food enters the intestine, it embarks on windy, lengthy journey. For most of the route, its surroundings don't appear to change much. But new research from Rockefeller's Daniel Mucida shows that the food-processing canal consists of compartments that pace the immune system's reactions to the food passing through—with less aggressive defenses in the first segments where nutrients are absorbed, and more forceful responses at the end, where pathogens are eliminated.

"The findings, published in Nature, provide new insights about how the intestine maximizes nutrient uptake while protecting the body from potentially dangerous invading microbes, two seemingly conflicting functions. The research has potential to improve drugs for gastrointestinal disorders, as well as inform the development of oral vaccines.

"'At first glance the intestine appears uniform throughout," says Mucida. "But we've found a sophisticated functional system lurking beneath the surface, organized in segments to allow different immune system functions in different locations."

"Mucida and colleagues uncovered a functional segmentation in mice by examining intestinal structures called gut draining lymph nodes, which orchestrate immune responses. The researchers found that nodes in different part of the intestine had different cell composition, and when they challenged the mice with a pathogen such as Salmonella, they saw different immune responses between segments.

"Having immune responses separated by location likely increases the chance that the immune system reacts appropriately to what's passing through, Mucida says. Once most nutrients have been absorbed, the system can focus more aggressively on eliminating pathogens without interfering with food uptake."

Comment: as long guts were developed, it is obvious the immune system had to be designed this way for protection from pathogens. if organisms waited for chance development, they have not survived to evolve further.