Immunity system complexity: sniffing out invaders (Introduction)

by David Turell , Wednesday, November 20, 2024, 22:51 (70 days ago) @ David Turell

Latest findings:

https://www.sciencedaily.com/releases/2024/11/241112123305.htm

"Immune cells are capable of detecting infections just like a sniffer dog, using special sensors known as Toll-like receptors, or TLRs for short. But what signals activate TLRs, and what is the relationship between the scale and nature of this activation and the substance being detected?

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"TLRs are found in great numbers on the surface of many of our cells, particularly those in the mucous membranes and those ofour immune system. They work like the olfactory receptors in our nose, being activated when they encounter a specific chemical signal. The alarm that they trigger starts a series of reactions inside the cells. When scavenger cells "sniff out" a bacterium, for instance, they initiate a process known as phagocytosis by engulfing and digesting it, while other immune cells release special messengers that call for reinforcements and thus provoke inflammation.

"There are several groups of TLRs, each of which responds to different "smells." "These are molecules that have crystallized into important danger signals over the course of evolution," explains Professor Günther Weindl from the Pharmaceutical Institute at the University of Bonn. Among them are lipopolysaccharides (LPS), which form integral parts of a bacterium's cell wall.

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"'We were able to demonstrate that these changes in the reflected wavelengths kick in just a few minutes after adding the signal molecule," says Weindl's colleague Dr. Janine Holze. "We also brought cells into contact with E. coli and Salmonella lipopolysaccharides. Although both components of the cell wall stimulate the same TLR, the reflected spectrum changed in a different way after introducing the E. coli LPS than after adding their Salmonella counterparts." This suggests that the same receptor is activated by different molecules in different ways and then triggers specific responses depending on the signal." (my bold)

Comment: these reactions are very specific and suggest strongly that they were designed.