![]() ![]() Whether it becomes a Th1 cell, a Th2 cell, or a Th17 cell (and perhaps we will discover others) will determine just in what ways it will assist in the war effort, and just what type of collateral damage - allergies, autoimmunity - might ensue.Įven though these mice were genetically engineered to produce a great abundance of T cells that target egg white protein, there is nothing within their genes that makes them react with tolerance or intolerance, because this is not a matter of genetics. But the decision does not end there war is much more complicated than friendship. If folly, the T cell becomes a helper T cell, ready to route out the enemy. If fruitful, the T cell becomes a regulator or suppressor T cell, and arranges a treaty of peace. The naive T cell puts its finger to the wind, so to speak, to distill the spirit of the times, and to discern whether an alliance with the protein would prove fruitful or folly. When the time comes, the decision proves all-engrossing: it is no less than the very decision to commit to immunological tolerance or to immunological intolerance. Depending on these tidings the naive T cell may on that fateful day become a brother to the protein, sheltering it from the reckless and wayward assaults of the more ignorant brethren, or may instead decide to sound the battle horn and launch an all-out crusade against the protein, ready to crush even its family and friends under the banner of victory. ![]() It is the molecular environment that will bode tidings of peace or of war. ![]() ![]() Having yet to fall into that fateful encounter with the protein of their destiny, they have yet to even decide whether that protein is friend or foe. We call these cells “naive” not to mock their credulity and lack of sophistication, but simply to indicate that because of their inexperience they have remained undecided and noncommittal about the courses their lives will ultimately take. The investigators took “naive” T cells from mice that had been genetically engineered to react to egg white protein, and then incubated the cells with that very protein and with different doses of the activated vitamins. These bad boys protect against infection, but they also appear to play a role in multiple sclerosis, rheumatoid arthritis, psoriasis, and inflammatory bowel disease. Th17 cells are helper T cells that produce a number of inflammatory chemicals, including interleukin-17. Vitamins A and D Synergistically Suppress the Development of Th17 Cells To address this issue, the investigators examined the effects of these vitamins on the development of Th17 cells and in a mouse model of contact hypersensitivity. If so, using the activated forms of both vitamins together might allow clinicians to treat these disorders using doses low enough to avoid the nasty side effects. The investigators thus sought to see if the activated hormone form of vitamin A, retinoic acid, might also prove useful in battling autoimmune disorders. One hardly wants to cure, say, psoriasis if it means having to pass kidney stones. A number of studies suggest that the activated hormone form of vitamin D, calcitriol, has great promise for preventing and treating autoimmune diseases, but its usefulness in the clinical setting is currently limited because it promotes excessive accumulation of calcium in the blood and soft tissues. A new Japanese study published last July in the journal Immunology Letters ( 1) provides further evidence of this synergy, this time suggesting the dynamic duo can courageously combat the most flagellant of our inner impulses, keeping our wayward neutrophils in check and barring them from wandering too far down the winding road that leads to autoimmunity. One of the perennial topics of this blog is the synergy between vitamins A and D.
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