Alternative Pathway

Serum factor B and Activated C3b (activated C3 will continuosly activate the complement system)
↓
C3bB
↓
Note: C3b is inactivated by factors H and I. But the introduction of LPS and other substances protects C3b from H and I hence C3b will be activated
↓
Activate serum factor D
↓
Cleavage of factor B
↓
C3bBb (stabilised by properdin) acts as a C3 convertase [this is where classical, alternative and lectin pathway meet]
↓
*Convertase activate C3
↓
(2 arrows forming C3a) C3b
↓
C3b and C4b2b forms C5 convertase
↓
(2 arrows forming C5a) C5b
↓
C5b bind C6 and C7
↓
Gather C8, forms small pores
↓
Forms pores with C9 [formation of the Membrane Attack Complex (MAC)]

*One C3 convertase can actually cleave many C3, this is thus the amplification step