Immunity system complexity: how sensor TLR8 works (Introduction)

by David Turell , Tuesday, April 14, 2020, 21:58 (1466 days ago) @ David Turell

A new discovery fighting intracellular bacteria:

https://www.sciencedaily.com/releases/2020/04/200414122826.htm

"Until now, the immune sensor TLR8 has remained in the shadows of science. A research team led by the University of Bonn has now discovered how this sensor plays an important role in defending human cells against intruders. The enzymes RNaseT2 and RNase2 cut ribonucleic acids (RNAs) of bacteria into small fragments that are as characteristic as a thumbprint. Only then can TLR8 recognize the dangerous pathogens and initiate countermeasures.

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" Like a radar system, the immune sensor with the scientific name Toll-like Receptor 8 or "TLR8" monitors whether tell-tale ribonucleic acids (RNA) appear during the recycling of dead cells or ingestion of live pathogens, indicating foreign invaders. This is because, as in a digestive process, complete cells and cell components that are no longer needed are taken up and broken down into their individual components and reassembled into new cell structures. If bacteria or other pathogens are hiding in these components, their different RNAs will appear on the radar screen of TLR8 during the recycling process.

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"...the researchers discovered two important tools of the immune system: RNaseT2 and RNase2. Both enzymes ensure that the immune sensor TLR8 is able to detect the tell-tale ribonucleic acids of bacteria and malaria in the first place. "You can perhaps picture long RNA as balls of wool, the loose end is not really visible," explains Thomas Zillinger, another lead author of the work from Prof. Hartmann's group. As long as the RNA are present as tangled balls, their sequence cannot be identified. TLR8 can only detect whether RNA comes from the host or an intruder once it has been broken down into readable fragments by RNaseT2 and RNase2.

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"'The interaction of RNaseT2 and RNase2 with the immune sensor TLR8 is a key element of the immune response against pathogens inside cells," says Bartok."

Comment: Intracellular bacteria are more of a problem than extracellular bacteria. tis complex defense mechanism must have been designed for living organ isms, or they would not have survived.