IMMUNOLOGY

Detailed explanation-1: -A number of proteins participate in the assembly of the MAC. Freshly activated C5b binds to C6 to form a C5b-6 complex, then to C7 forming the C5b-6-7 complex. The C5b-6-7 complex binds to C8, which is composed of three chains (alpha, beta, and gamma), thus forming the C5b-6-7-8 complex.

Detailed explanation-2: -C5b binds to one unit of C6, which through a conformational change weakens the bond between C5b and C5 convertase allowing C7 protein to bind.

Detailed explanation-3: -C5b-C9, termed the complement membrane attack complex is responsible for the cytolytic function of complement, a potent mechanism contributing to innate defence against pathogens.

Detailed explanation-4: -C5b can bind to cell membranes and organize the assembly of complement components C6 through C9 into a so-called membrane attack complex. These proteins bind together and organize the formation of a pore in the cell membrane of bacteria or mammalian cells.