There are many mechanisms by which the body responds
to foreign invaders. One of these involves the T-cells of the
immune system, which have a number of different proteins on their
surface called ‘checkpoint proteins.’ These checkpoint proteins
bind to proteins on the surface of other cells and can result in
either stimulation or suppression of T-cell activity. Normally,
surface proteins on foreign or invading cells will produce a
stimulation of T-cell activity against these cells, while T-cell
suppression is a built-in mechanism to prevent the immune system
from attacking the body’s own normal cells.
