| ▲ | atombender 2 days ago | |
Streptococcus pyogenes (group A streptococci) are well known for being able to form this kind of biofilm [1] and stay hidden from the immune system. Chronic strep throat (sometimes leading to guttate psoriasis) are thought to be due to this feature. The bacteria can form these biofilms in many places, including the tonsils. It's implicated in things like periodontitis. (Another streptococcus, S. mutans, causes cavities.) They're very sneaky bacteria, due to what's called molecular mimicry. The bacterial surface has a protein called M protein, and some of this protein's epitopes (stretches of amino acids) are the same or similar to human proteins like myosin, similar enough that antibodies cause cross-reactivity with human tissue. This is why strep bacteria can cause rheumatic fever and some other diseases. Strep has also been implicated in psoriasis; we have good evidence that the cross-reactivity is what kick-starts the disease and is in some way responsible for why it's chronic. | ||