Do leukocytes of the innate immune system (natural killer cells, neutrophils, etc) detect that something is foreign via pattern-recognition receptors? If not, how do they determine the difference between self and non-self? (is it simply because pathogens don't have self markers (MHC I markers) on their surface.
Thanks everyone for answering so many questions
Not sure about neutrophils,
But my teacher said NK cells essentially just roam around the body trying to bind to “kill” receptors on self cells. If the self cells are normal and not infected by a virus infected or are a cancer cell, then the MHC 1 marker inhibits this signal. However, if they ARE a cancer or virus infected cell, then they will likely have abnormal MHC markers that don’t inhibit the kill signal, as a result, the NK cells degranulate, releasing perforin and granzymes to induce apoptosis in the abnormal self cell.
Now I have a question, can someone see if what I’m saying makes sense?
A substitution mutation where an amino acid changes, would impact the protein formed like this:
It would alter the primary structure of the protein, which in turn could affect the tertiary structure as it may alter bonds that form the protein’s specific 3D shape. As a result, a different tertiary structure resulrs, which may not be specific to the function of the protein, inhbiiting it from being able to perform its function.