Întrebarea e oarecum stupidă, dar mecanismul gândirii (simplul fapt de a gândi) e drăguț. E genul de întrebare/întrebări pe care niciun student în ziua de azi nu are curiozitatea și interesul s-o/să le formuleze. Bineînțeles că mă văd pe mine ridicând mâna la sfârșitul cursului pentru a întreba ceva de felul acesta, când toată lumea abia așteaptă s-o taie din loc, pufăind pentru că îi somez să mai aștepte 5 minute în ”pușcăria universitară”. Păcat că nu am descoperit siteul ”quora” ceva mai devreme.
Can water molecules bind to IgE receptors and trigger an
allergic reaction?
Or are the mast cell receptors always surrounded by water molecules in the dermis, mucosa, etc? (extracellular fluid?)
Basically I'm asking, can water molecules trigger mast cell release like say, peanut proteins do.
There are people who say they are so allergic to plain H2O, they cannot even drink it, (so it is not just on the skin!) but these claims are unproven.
What if the IgE receptor on the mast cells was hydrophilic? Would water bind to it? Also, aren't there receptors in the body that bind molecules as small as amino acids (neurotransmitters?)
Basically I'm asking, can water molecules trigger mast cell release like say, peanut proteins do.
There are people who say they are so allergic to plain H2O, they cannot even drink it, (so it is not just on the skin!) but these claims are unproven.
What if the IgE receptor on the mast cells was hydrophilic? Would water bind to it? Also, aren't there receptors in the body that bind molecules as small as amino acids (neurotransmitters?)
Christopher Wells, Chemistry Double PhD from SUNY Albany, NY (May 2011)
Aquagenic
itching and urticaria are two of the so-called water allergy
disorders. Unlike peanut allergies, the reactions that produce itching
and hives upon contact with water are not related to histamine release
(as with mast cell degranulation and most allergies). Inhibiting
histamine release or receptors would have limited effectiveness on these
disorders. Using capsaicin does help, as it deadens the pain
sensations by forcing the nerves to use up their reserves of messenger
chemicals. As many histamine-related allergies involve immunoglobin
interactions with proteins, aquagenic allergies generally do not involve
these interactions. In some cases, the reactions occur anytime water
is involved, such as drinking, showering, swimming, or bathing. The
reactions are generally restricted to the skin or surfaces in contact
with water, and are related to ion interactions between the skin and the
dissolved ions in water (since chloride and fluoride ions tend to flare
up these reactions). Thus, water allergies are not a product of
immunoglobin interactions, but rather high sensitivity towards dissolved
ions present in water.
There
are types of 'hypersensitivity' to water, such as aquagenic urticaria,
which causes allergy-like symptoms on contact with water, but the
difference is that unlike 'true' allergies, they do not cause Mast Cell
activation, which is the determining factor in determining whether or
not it is a true allergy or not.
As well, as many others have mentioned, if water was able to bind to IgE receptors and cause a true allergic reaction, there would be many problems since your body is mostly water:
1) Constant immune activation would cause stress on your body; most likely leading to excess cortisol secretion.
2) Water binding to IgE would cause autoimmune based reactions and due to the amount of activation of IgE, it would cause many problems, like cytokine storms, increased permeability of vessels, etc.
To answer the edits:
1) In general, you're confusing what Ig receptors can and can't bind. Usually, Ig receptors only bind short (4-20) chains of amino acids. They can also recognize fats and other organic compounds. From my knowledge, they cannot bind purely 'chemical' susbtances such as water, lead, gold, etc. The point of the receptor being hydrophobic is to prevent water from entering the receptor and messing up binding of substances it can actually bind to; a sort of competitive inhibition.
2) Yes, there are receptors that can bind amino acids; Ig receptors being one of the. As well, there are receptors along cells and within cells (such as Toll-like receptors) that bind viral peptide segments specifically for inter and extra-cellular pathogenic recognition.
https://www.quora.com/Can-water-molecules-bind-to-IgE-receptors-and-trigger-an-allergic-reaction
As well, as many others have mentioned, if water was able to bind to IgE receptors and cause a true allergic reaction, there would be many problems since your body is mostly water:
1) Constant immune activation would cause stress on your body; most likely leading to excess cortisol secretion.
2) Water binding to IgE would cause autoimmune based reactions and due to the amount of activation of IgE, it would cause many problems, like cytokine storms, increased permeability of vessels, etc.
To answer the edits:
1) In general, you're confusing what Ig receptors can and can't bind. Usually, Ig receptors only bind short (4-20) chains of amino acids. They can also recognize fats and other organic compounds. From my knowledge, they cannot bind purely 'chemical' susbtances such as water, lead, gold, etc. The point of the receptor being hydrophobic is to prevent water from entering the receptor and messing up binding of substances it can actually bind to; a sort of competitive inhibition.
2) Yes, there are receptors that can bind amino acids; Ig receptors being one of the. As well, there are receptors along cells and within cells (such as Toll-like receptors) that bind viral peptide segments specifically for inter and extra-cellular pathogenic recognition.
https://www.quora.com/Can-water-molecules-bind-to-IgE-receptors-and-trigger-an-allergic-reaction
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