Question

Ch 15..answer this question concerning The Complement System:

Where does the activation of complement system take place?

What molecule is responsible for the activation of complement system?

How is the bacterial cell going to be destroyed eventually?

Answer 1

Most compliment components are present in the serum in functionally inactive forms. Complement activation involves activation of one component that triggers the activation of next component.

There are three pathways of compliment activation :

1. Classical pathway- activation occurs by formation of antigen-antibody complex.

2. Lectin pathway- activated by binding of mannose binding lectin to mannose residue on bacterial cell, hence discriminates between self and non-self.

3. Alternative pathway - activation is triggered by almost any foreign substance.

Activation of compliment results in the production of several biologically active molecules which contribute to killing of bacterial cell. The most important action is to facilitate the uptake and destruction of bacterium by phagocytosis.