> Does our immune system not have any way to fight prions?
The normal and misfolded versions of a prion have the same protein sequence. This lack of differentiation allows the pathogenic form of prions to remain undetected by the immune system.
I understand that it’s the same sequence but the immune system doesn’t “know” about the sequence, it “knows” about the shape, no? Seems like a misfolded protein would have a different shape and receptors would bind to it differently.
You’re right, antibodies are able to recognize shape. Several early steps of the immune response, however, are independent of conformation. For example, in order to be presented, protein antigens are usually processed and chopped into small peptides, and these may be similar between both prion variants. Additionally, prion proteins can be resistant to that sort of processing.
The normal and misfolded versions of a prion have the same protein sequence. This lack of differentiation allows the pathogenic form of prions to remain undetected by the immune system.