Nucleated cells are always presenting peptides to circulating T-cells on MHC Class I. If the cell were infected by something like a virus:
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PRRs on the cell could have detected DAMPs or PAMPs and it would be expressing costimulatory proteins like B7 on the membrane.
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At any one time the various MHCs on the surface would still be presenting a mix of both self and non-self peptides. Just because a cell is infected doesn't mean it totally stops expressing self-peptides on MHC, right?
T-Cells would get Signal 1 from the non-self peptide + MHC, and Signal 2 from the B7 protein. This combination of signals lets it know that the non-self peptide is indeed foreign and for that T-cell specific to that foreign peptide to activate fully. Pretty standard stuff.
But... during this time MHC is still also presenting self peptides. Wouldn't these self peptides + MHC also be sitting next to B7 proteins?
T-cells that have intermediate binding strength to self peptides survive thymic selection. If such a T-cell bound to this MHC + self peptide along with a B7, wouldn't it get fully activated against this self peptide?
During a time when a cell is expressing B7 / Signal 2, is there some kind of mechanism where B7 is only expressed next to MHCs containing non-self peptide, and not next to the other MHCs containing self peptide?
Edit:
Hmmm... perhaps there's a time component?
https://www.quantamagazine.org/immune-cells-measure-time-to-identify-foreign-proteins-20190603/#:~:text=The%20white%20blood%20cells%20called,and%20those%20of%20invading%20pathogens.
So yes, T-cells do still bind to MHC + Self Peptides on infected cells along with Signal 2 / B7, but because the self peptide bond is weak, it binds for a short amount of time and is thus deemed safe and no further activation of that T-cell happens.
Steven Speilberg said he would not subtitle the Spanish parts of West Side Story as he did not want to take power away from Spanish speakers. WTF does this even mean... It makes absolutetly no sense and unnecesarily will make the majority of viewers miss parts of the dialogue. If anything, subtitles empower the Spanish speakers as it allows non-Spanish speakers to understand Spanish characters better. The lack of subtitles simply alienates both sides.
Also, this is a movie. The whole point is for it to be understandable. Why is it that if you watch this movie in other countries the English is subtitled but not the Spanish. It makes no sense and Speilberg should stop being applauded for this ridiculous decision
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I was recently on degutopia reading the page about colour varieties in our precious goobers (link: http://www.degutopia.co.uk/degucolours.htm), and as also said on that page, all of the colour varieties that aren’t the natural agouti color require a lot of inbreeding for pups with these coat colors, thereby creating a poor gene pool and bringing alot of health issues with that. All the way at the top of the page, it is said that “breeders in Europe are working hard to try and correct these problems in coloured degus”. Judging by the most recent date i saw on this page, 2017, it has been awhile since they updated it, my question was does anyone know if said breeders have actually reached their goals and improved the health of these degus?
My precious degu Sam died last week while only being 3, and he was a sand guy. Im looking for two young companions for his buddy Frodo, and i’m interested in blue degus, but i don’t want to get goobers that will have to suffer from health issues simply because their desired colour forces them to be offspring of inbreeding and a poor gene pool.
