Alternative PW

Question 1

Initiation

Answer 1

C3 directly binds to the microbe, causing spontaneous hydrolysis into C3a and C3b

Question 2

Process

Answer 2

C3 directly binds to the microbe, causing spontaneous hydrolysis into C3a and C3b

C3b binds to Factor B

Factor D cleaves Factor B into FBa and FBb

C3bFBb is the alternative pw’s equivalent of C3 convertase

C3bFBb cleaves C3 into C3a and C3b, C3b attaches to microbe and forms C5 convertase–> rest of the steps are identical to Classical PW