Immunity system complexity: how T cells react to pathogens (Introduction)

by David Turell @, Tuesday, June 16, 2020, 21:07 (1381 days ago) @ David Turell

Sometimes they 'relax':

https://phys.org/news/2020-06-cells-critical-immune-response.html

"Like finding that needle in the haystack every time, your T cells manage what seems like an improbable task: Quickly finding a few invaders among the many imposters in your body to trigger its immune response.

"T cells have to react fast and do so nearly perfectly to protect people from diseases. But first, they need a little "me" time.

"Rice University researchers suggest that has to do with how T cells "relax" in the process of binding to ligands—short, functional molecules—that are either attached to the invaders or just resemble them.

"The look-alikes greatly outnumber the antigen ligands attached to attacking pathogens. The theory by Rice chemist Anatoly Kolomeisky and research scientist and Rice alumnus Hamid Teimouri proposes that the T cell's relaxation time—how long it takes to stabilize binding with either the invader or the imposter—is key. They suggested it helps explain the rest of the cascading sequence by which invaders prompt the immune system to act.

"The inappropriate activation of a T cell toward its own molecules leads to serious allergic and autoimmune responses.

***

"'It is amazing how T cells are able to react so fast and so selectively. This is one of the most important secrets of living organisms," said Kolomeisky, a professor and chairman of Rice's Department of Chemistry and a professor of chemical and biomolecular engineering.

***

"In a "very speculative" suggestion, the researchers noted that when the binding speed of imposters matches that of invaders, triggering both biomolecular cascades, there's no immune response. When the more relaxed binding of pathogenic ligands lags behind, it appears more likely to reach a threshold that triggers the immune system. Kolomeisky said the concept could be validated through experimentation.

"He and Teimouri wrote that many other aspects of T cell triggering need to be explored, including the roles of the cellular membranes where receptors are located, cell-cell communications, and cell topography during interactions. But having a simple quantitative model is a good start."

Comment: The T cells are programmed to perform certain immune responses. We are still learning how all of the design responses work to sort out the confusing signs.


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