The complement system

Question 1

Characteristics of complement system?

Answer 1

Complement system consists of more than 30 proteins/factors that are found in the plasmas, present in an inactive form.

They are activated in a cascade (protein recruits protein and so on..) –like format
activation of the complement in fact takes place on the surface of the target cells.

Question 2

What are the three main pathways of complement system?

Answer 2

Alternative pathway, classical pathway and lectin pathway

Question 3

Characteristics of alternative pathway activation?

Answer 3

microbe triggers alternative pathway
triggers complement cascade

Question 4

Characteristics of classical pathway activation?

Answer 4

need involvement of specific antibodies like IgG
triggers complement cascade

Question 5

Characteristics of lectin pathway activation?

Answer 5

A specific molecule can be recognized by a specific protein able to bind
triggers complement cascade

Question 6

What is the MAC?

Answer 6

Membrane Attack Complex
structure at end of complement cascade
pore on surface of specific cell involved

Question 7

What are the functions of the complement?

Answer 7

Direct lysis of target cells.

Some products increase blood flow and act as chemo-attractants and recruit other immune cells to the site of infection to enhance the immune response.

Other products facilitate and enhance phagocytosis (opsonization)

Question 8

What are the names of the different ways immunity can be achieved?

Answer 8

Active immunity and passive immunity

Question 9

What happens in active immunity?

Answer 9

-Host own immune system actively involved in the production of antibodies and development of immunity
-weeks to develop
-memory cells produced
-permanent/ long term effect

Question 10

What happens in passive immunity?

Answer 10

-Host immune system is passively involved, antibodies were not produced by immune system but from another individual.
-immediate development
-no memory cells produced
-temporary/ short effect