Ficolin-1 binds to molecular patterns on the target cell surface
Ficolin-2 binds to molecular patterns on the target cell surface
Ficolin-3 binds to molecular patterns on the target cell surface
MBL binds to repetitive carbohydrate structures on the surfaces of viruses, bacteria, fungi, and protozoa
Activation of MASPs
Activation of C1R
Activation of C1S
Conversion of C4 into C4a and C4b
C4b binds to cell surface
Conversion of C2 into C2a and C2b
Formation of Classical C3 convertase (C4b:C2a complex)
Spontaneous hydrolysis of C3 thioester
Factor B binds to C3(H2O)
Factor D cleaves C3(H2O)-bound Factor B
C3(H2O):Factor Bb cleaves C3 to C3b and C3a
C3b binds to cell surface
Factor B binds to surface-associated C3b
Factor D cleaves C3b-bound Factor B
Properdin stabilizes C3b:Bb bound to cell surfaces
Formation of alternative pathway C5 convertase
Initial triggering of complement
Creation of C4 and C2 activators
Lectin pathway of complement activation
Ficolins bind to repetitive carbohydrate structures on the target cell surface
Classical antibody-mediated complement activation
Alternative complement activation