NCIt definition : These genes encode more than 30 proteins of the complement system engaged in host
defense. This system provides both an independent immune system capable of attacking
microbes as well as other foreign material and an adjunct to the antibody system.
Once activated, the complement system fires in a cascade-like fashion in which one
component activates the next. Both swift and powerful, millions of complement components
can deposit on an invading microbe within only a few minutes. Such a potent system
requires strict regulation to avoid host injury. Membrane cofactor protein (MCP) is
one critical regulator aimed at controlling inadvertent complement activation on host
cells and nearly every cell examined expresses MCP on its cell membrane.;
Semantic type(s)