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COMPLEMENT SYSTEM PowerPoint Presentation
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COMPLEMENT SYSTEM

COMPLEMENT SYSTEM

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COMPLEMENT SYSTEM

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  1. COMPLEMENT SYSTEM DrFarzana Salman

  2. Antibodies act mainly in two ways 1. By direct attack on the invader 2. By activation of the complement system.

  3. Direct Action of Antibodies • Agglutination • Precipitation • Neutralization • Lysis

  4. COMPLEMENT SYSTEM

  5. Complement system • Twentyor so proteins that circulate in the blood in an inactive form • Mostly enzyme precursors • These proteins named • C1 to C9 • Factors B and D.

  6. Complement system can be activated by two pathways 1. Classical Pathway 2. Alternative pathway.

  7. Classical Pathway of compliment system

  8. Effects are : 1.Opsonization and phagocytosis -C3b strongly activates phagocytosis by neutrophils and macrophages 2.Lysis -C5b789 is called a lytic complex. -rupture cell membrane of bacteria or other invading organisms.

  9. 3.Agglutitation -change surfaces of the invading organisms -adhere to one another. 4.Neutralization of viruses -attack the structure of some viruses and make them non virulent. 5.Chemotaxis -C5a initiates chemotaxis of neutrophils and macrophages to the area adjacent to the antigenic site.

  10. 6.Activation of mast cells and basophils -C3a,C4a, and C5a activate mast cells and basophils • Release histamine, heparin • increase local blood flow • Increase leakage of fluid and plasma protein into the tissue • Local tissue reactions that help immobilize the antigenic agent.

  11. 7.Local Inflammation Increased blood flow to increase further Capillary leakage of proteins increases further Interstitial fluid proteins to coagulate in tissue spaces

  12. Alternate pathway. • In alternate pathway • Polysaccharides of the invading organisms combine with Factor B, D . • This complex activates C3 to C3a and C3b • Onward reactions are the same as in classical pathway.

  13. Alternate pathway. • In alternate pathway • Polysaccharides of the invading organisms combine with Factor B, D . • This complex activates C3 to C3a and C3b • Onward reactions are the same as in classical pathway.