Which of the following can be directly activated as a soluble protein in the microenvironment surrounding a pathogenic cell?

Which of the following can be directly activated as a soluble protein in the microenvironment surrounding a pathogenic cell?

Which of the following can be directly activated as a soluble protein in the microenvironment surrounding a pathogenic cell?











A. C2
B. C3
C. Factor B
D. Factor D
E. C4













Answer: B