4 ms·
"...memory CD4s proliferated and otherwise became activated in response to exposure to certain components of the influenza virus, but also to epitopes of severa
by hirundo 7y ago
"...memory CD4s proliferated and otherwise became activated in response to exposure to certain components of the influenza virus, but also to epitopes of several different bacterial and protozoan microbes. This cross-reactivity could explain why exposure to common bugs in the dirt and in our homes renders us less susceptible to dangerous infectious agents."
So the CD4 is a key activated to fit a particular lock, but given the imperfections of locks it fits a random assortment of others too. As we build up a keychain of these we have a better chance to fit any random lock.
But why doesn't the larger keychain also increase the chances of auto-immune diseases when they happen to fit our own locks? Or increase inflammation from other benign microbes it fits? Seems like the metaphor needs work.
- nullc 7y ago> But why doesn't the larger keychain also increase the chances of auto-immune diseases, when they happen to fit our own locks? The process that generates immune cells tests them for autoimmune reactivity and aggressively culls ones that are.
- nomel 7y agoCould you provide the name for this, or something I could search for? This is fascinating.
- rcthompson 7y agoLook up the function of the thymus in T-cell development and selection. https://en.wikipedia.org/wiki/Thymus#Function https://en.wikipedia.org/wiki/Thymus#Function
- alextheparrot 7y agoThe term is "Central Tolerance". The Thymus (Which someone else mentioned) effectively checks the following: (1) Does the cell react to an antigen (Foreign particle) [β-selection] (2) Does the cell still work with the immune system (Can it bind to the cells it needs to bind to once it finds the antigen) [Positive Selection] (3) Does the cell recognize only foreign particles and not the body itself [Central Tolerance / Negative Selection]
- mirimir 7y agoSure, but it doesn't always work :( I had the misfortune of blowing out my right knee and acquiring a chlamydia infection ~simultaneously. And then developed acute rheumatoid arthritis. Which has progressed, albeit slowly, ever since. So it goes.
- three_seagrass 7y agoYou do get autoimmune diseases this way. The thyroid does a good job of filtering out new immune cells that attack the body, but sometimes you will get an infection where the targeted protein mimics a body protein. When that happens, you're stuck with an autoimmune disease. Example: https://en.wikipedia.org/wiki/Reactive_arthritis https://en.wikipedia.org/wiki/Reactive_arthritis
- zby 7y agoI think you meant thymus not thyroid.
- three_seagrass 7y agoYes, you're right. My bad.
- hateful 7y agoI may have this wrong, but this can also lead to certain allergies. https://www.youtube.com/watch?v=kLC0cX3rAX0 https://www.youtube.com/watch?v=kLC0cX3rAX0
- nradov 7y agoThe hygiene hypothesis might play a role here. Early exposure to certain pathogens could have a protective effect against autoimmune disease. https://en.wikipedia.org/wiki/Hygiene_hypothesis https://en.wikipedia.org/wiki/Hygiene_hypothesis
- deleted 7y ago[deleted]