1. Complement & Complement Fixation
Hugh B. Fackrell

2. Content Outline Complement Components Complement Activation
Biological Consequences
Complement Fixation

6. Complement system

7. Phases in the Complement Cascade
Recognition
Activation Amplification
Membrane Attack

8. Complement Cascade

9. Complement Activation
Classical pathway
Alternative pathway
Membrane attack complex

10. Complement Components
The Classical Pathway

11. Membrane Bound Antigens

12. Soluble Antigen

15. C4

16. C2b

17. C3

18. C5

19. C5a & C5b

20. C6

21. C7

22. C7 becomes hydrophobic

23. C8

24. C8 in membrane

25. C9

26. C9 pore

28. An Alternative Complement Pathway
Part of Innate immunity
Activated without Antibody

29. Alternate Vs Classical Paths

30. Regulation of Complement

32. Biological Consequences
Cell lysis
Inflammation
Opsonization
Viral neutralization
Solubilization of immune complexes

36. Complement Fixation Test
Fig 18.8

37. Complement Fixation Assay Test Phase
Positive serum
antibodies
Antigen
Complement
AG-AB complex formed
Complement used up
Negative serum
no antibodies
Antigen
Complement
No Ag-Ab complex
Complement NOT used up
No visible difference!!!

38. Complement Fixation Assay Indicator phase
Positive Test phase
No complement
Indicator system
Sheep RBCs
Anti sheep RBCs
Result
NO LYSIS of RBCs
CLOUDY
Negative test phase
Complement
Indicator System
Sheep RBCs
Anti Sheep RBC’s
Result
LYSIS of RBCs
CLEAR

39. CF: Advantages Reagents easily available
Semi quantitative or quantitative
Wide application
Extremely sensitive

40. CF: Disadvantages Indirect Test Need adequate controls
Reagents unstable
Quantitation time consuming
Cannot be automated

41. DONE!!!