"NK cells generally kill cells that display non-self MHC I-peptide
complexes" -- that is, non-self MHC;
"CD8 cells kill only cells bearing a specific non-self antigen: -- that is,
self MHC + non-self antigen.
An infected self cell falls into the second category so you need CD8 T cells
to kill it. You need another type killer cell(s) to destroy self cells that
no longer express MHC or non-self cells that express non-self MHC. Some
viruses downregulate MHC in self cells they infect.
<suaysuay at atenista.net> wrote in message
news:20030127130038.16153.qmail at ww02.hostica.com...
> I'm confused about this one very basic aspect of immunity:
> NK cells generally kill cells that display non-self MHC I-peptide
complexes, CD8 cells kill only cells bearing a specific non-self antigen.
Given that viruses mutate, and NK cells seem to have a 'better safe than
sorry' attitude, wouldn't NK cells be "better" than CD8 cells in clearing up
an infection? Why is it that in some viral infections, NK cells are only
good for controlling the infections but CD8 cells are needed to finish the
job?
