I’ve heard about antibodies, but how does your immune system physically attack or destroy a virus? Or in the case of someone with something like MS, how does your immune system physically attack your nervous system?
In: 3
There’s lots of ways to do it. First you need recognition:
– Many different white cells have receptors that can recognize when something is covered in complement proteins or antibodies.
– Also many cells have receptors capable of recognizing molecules common to particular classes of pathogens, like LPS in gram-negative bacterial membranes, or molecules associated with damage to other cells of the own body, like DNA (which belongs strictly inside your cells’ nuclei).
– Particular cells of the *adaptive* immune system — T and B cells — can generate their very own unique receptor that can recognize one very specific molecular pattern.
Once you’ve got recognition, there are then a couple of ways to attack a virus, cell or larger thing:
– Eat & digest it
– Dump harmful molecules on it
– Bog it down with antibodies
– Let complement poke it full of holes
– If inside an infected host cell, trigger that cell’s self-destruction to force it out in the open and *then* do any of these other things
Hope that’s broadly informative.
In the specific case of MS, people have B cells that have somehow become sensitized to myelin. Myelin is a molecule that forms a sheath around nerves, which hugely improves their ability to quickly transmit electrical signals (and you depend very much on that working correctly). These B cells produce antibodies, which will end up binding to myelin wherever they find it, and once they’re bound, any other passing white cell with antibody receptors will think “well, this has antibodies stuck to it, so it’s gotta be bad”, and attacks the myelin sheath. That’s mostly T cells going the *dump harmful molecules* route.
Latest Answers