NCIt definition : A heterotrimeric protein complex composed of complement component 8 (C8) chains alpha,
beta and gamma. The alpha and gamma chains form a disulfide-linked dimer that is noncovalently
associated with the beta chain. C8 inserts itself into target cell membranes following
formation of the C5b-6-7 complex and then recruits 10-16 molecules of C9 to complete
the formation of the membrane attack complex.;