23. Humoral defence mechanisms. Complement.

Question 1

Humoral Responses

Answer 1

• Blood clotting - during injury
• The completment system - proteins with protective roles

Question 2

Similarities of blood clotting and complement system

Answer 2

• Consists of plasma proteins
• job is to respond to a stimulus caused by external injury
• most of the proteins are protease
• stimulus causes their components to activate each other through limited proteolysis, forming a cascade.

Question 3

The completement system

Answer 3

• involves a series of proteins found in the blood that are part of the immune responses
• set of proteins made in liver, transported into the blood waiting for a breech in normal functioning of the human body

Names of these proteins:
c1, c2, c3, c4, c5, c6, c7, c8, c9 - cylindrical channel

COMPLETEMENT SYSTEM:
1. Classical Pathway
2. Lectin Pathway
3. Alternative Pathway

– Classical Pathway (cascade of event, one, triggers the next, which triggers the next)
1. Pathgen gets into ur system, has antigens on the surface, that is recognised by an antibody
2. They bind together, C1, binds to the antibody.
Antigens complex, and gets activated
3. Causes c2 and c4 to split into 2
4. One fragment from c2 joins with one fragment from c4 to form an enzyme called c3 convertase
5.c3 convertase splits into 2 and form c3a and c3b
6. c3a diffuses out and ittrads other phagocytes into the area
7. c3b fragment will bind to the surface of the pathogen and tags the pathigens for destruction
- c3b causes c5 to split into 2, to becme c5a and c5b. c5b joins with c6-c9 to form the membrane attack complec
- membrane attaches to membrane of pathigen, makes a hole
- water rushes into the pathogen causing it to break apart

– Alternative Pathway
c3 binds directly to the pathogem interacts with other proteins, factor P;B;D interaction causes c3 to split into c3a + c3b
- pathaway continues as the classical system