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Now that everyone is interested in immunology can we talk about how cool of a protein AIRE is?
As requested: How can we tell our proteins apart from viruses/bacteria? A 
on a cool protein: Autoimmune regulator (AIRE). AIRE is a transcription factor that’s found in the thymus – this is where your T cells learn what’s you (self) 1/10
on a cool protein: Autoimmune regulator (AIRE). AIRE is a transcription factor that’s found in the thymus – this is where your T cells learn what’s you (self) 1/10
A transcription factor is something that signals for your cells to produce RNA from DNA – not all cells express all the proteins in your genome. UNLESS you’re in the thymus. 2/10
This little guy – AIRE – can open up random bits of your genome and transcribe RNA to show resulting proteins your T cells. Proteins from your brain, your liver, your bones, your eyes, you name it. 3/10
So in your thymus (which is right above your heart and bigger when youre a kid), AIRE goes around your genome reading off random bits so that your T cells can learn what proteins are you – if a T cell reacts against a part of you, its deleted. That T cell is gone. 4/10
If your T cell has a randomly generated sequence that doesnt recognize any peptides generated by AIRE, then it has the green light – it has passed the self-recognition test & its allowed to go and look for what it might recognize (something that is not you, or non-self). 5/10
This process is completely statistical! Your T cell receptors are generated by random rearrangement of your genes (through another cool enzyme called RAG) which creates a massive possible pool of T cell types. 6/10
There are a QUADRILLION (15 zeros) possible combinations of genes to make unique T cells. After selection in the thymus against the T cells that react with your own proteins and cells (which we don’t want), 7/10
...there are about 100 million types of T cells to react to the different viruses and bacteria and help fight those off (which we do want). 8/10
So how does our body know that a protein that our body made is not supposed to be there (ex. mRNA vaccine). 9/10
THANK YOUR THYMUS, and more specifically, AIRE. AIRE showed your T cells where everything was in your house (body), and what everything was (furniture) so when all of the sudden you find a Koala in your Christmas Tree, you know it shouldn’t be there. 10/10 https://www.theguardian.com/environment/2020/dec/03/on-the-first-day-of-australian-family-finds-live-koala-in-their-christmas-tree
