FIGURE 2.

Schematic diagram of three activation pathways of the complement. There are three pathways to activate the complement system: classical pathway (CP), lectin pathway (LP), and alternative pathway (AP). All three pathways lead to the production of C3 invertase and C5 invertase, which cleave C3 and C5 respectively, and the C5 is then cleaved to form C5a and C5b, in that C5b combines with C6 and C7 to form a C5bC6C7 complex which is inserted into the cell membrane. The complex binds to C8 and joins with C9 to form a membrane attack complex (MAC). Finally, the cell starts to lyse. MBL, mannose‐binding lectin; MASP, MBL‐associated serine protease; FB, Factor B; FD, Factor D; FP, Factor D; MAC, membrane attack complex (C5b‐9)