Immunity complexity: mucosal T cells (Introduction)

by David Turell , Monday, December 23, 2019, 18:50 (1579 days ago) @ David Turell

Specialized protective cells studied:

https://medicalxpress.com/news/2019-12-insights-armies-strategically-stationed-cells.html

"The immune system mounts robust responses to infections, vaccines and cancer, but only now have scientists fully begun to unravel how non-circulating populations of T cells that reside in the body's "mucosal barrier tissues" keeps threats at bay.

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"...the body has armies of T cells that stake out posts in mucosal tissues—and they don't stray from these local compartments. These mucosal tissues can be found at vulnerable ports of entry into the body—the mouth, anus and vagina—as well as other important areas where disease exposure is a possibility and inflammation is likely.

"The Hutchinson scientists zeroed in on a receptor dubbed CCR5+ and demonstrated that even when this T cell component is inhibited, the T cell in its mucosal compartment remains fully functional—fighting infection and thwarting cancer.

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"Our data suggest that the human CCR5+ tissue-resident memory T cell compartment is functionally and spatially equipped to maintain barrier immunity," the Hutchinson team wrote.

"The human body's mucosal barriers are first lines of defense—physical barriers of immune system protection. The mucosal barriers have been defined as some of most efficient and elegant forms of nature's biological engineering. For instance, the gastric mucosal barrier, wrote Dr. Kenneth E.L. McColl in 2012, "is an example of superb natural engineering" because it has to withstand a most hostile chemical environment of highly acidic and proteolytic gastric juice, which rapidly kills swallowed microorganisms and breaks down ingested foods." (my bold)

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"Resident T cells also are found in the cervicovaginal tract, a potential port of entry for viral pathogens, particularly HIV and herpes simplex virus, among others. T cells that reside in barrier mucosal tissues are important because they are non-circulating and provide local defense against viruses, Prlic and colleagues say.

"CCR5+, which stands for chemokine receptor 5, is a cell receptor on activated T cells, which orchestrates how immune cells migrate to sites of inflammation in the body.

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"They concluded: "The human tissue-resident CCR5 T cell compartment maintains protective and functional properties during inflammation.'"

Comment: Another complex layer of immune protection is outlined requiring specialized protein molecules which a chance process could not find in the millions of molecules possible. Note my bold about the gastric lining. Gastric juice is like battery acid. A stepwise development of the acid and protection for the lining is impossible. Only design fits.