1 / 16

Principles of Immunology Complement 2/7/06

Principles of Immunology Complement 2/7/06. “Nothing is to be more prized than the value of each day” Goethe. Word List. Complement fixation Heat labile Immune complexes Opsonization Proenzymes. History. Bordet-Heat labile substance in the serum

kira
Download Presentation

Principles of Immunology Complement 2/7/06

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Principles of ImmunologyComplement2/7/06 “Nothing is to be more prized than the value of each day” Goethe

  2. Word List • Complement fixation • Heat labile • Immune complexes • Opsonization • Proenzymes

  3. History • Bordet-Heat labile substance in the serum • Ehrlich-Named it complement because it completes the action of lysis when coupled with antibody • Wasserman-Complement fizxation(CF) test for syphilis

  4. CF Test Step 1-Mix unknown serum with Ag of known pathogen Step 2-Add Complement Step 3-Add Ab-coated RBCs to test system Possible outcomes: RBCs lyse RBCs don’t lyse Interpretation?

  5. Effects of Complement • Cell lysis • Ab dependent • Ab independent • Opsonization • Inflammation • Clearance of Immune complexes • Viral neutralization

  6. Complement Precursors • ~ 5% of serum globulin • Proenzymes (zymogens)-proteins or glycoproteins • Continuously circulate in inactive state • Source-hepatocytes, monocytes, macrophages, epithelial cells

  7. Complement Components • C1 through C9 • Numbered in order of description, not sequence of action • Enzymatic reaction triggered by one of three mechanisms • Antibody-Antigen • Microbial or non microbial foreign substances • Mannose binding lectin

  8. Classical Pathway • Adaptive immunity • C1 binds to Ag-Ab complex • Activated C1 cleaves C4 and C2 • Formation of C3 convertase • C3 is cleaved • C5 is cleaved • Sequential binding of C6-C9

  9. Alternative Pathway • Innate immunity • Spontaneous cleavage of C3 based on multiple initiators • Requires Factors B and D • Formation of C3 convertase (less stable) • requires properdin

  10. MB Lectin Pathway • Innate immunity • MB Lectin bound to microbial cell wall components • Follow-up binding of serine proteases • This complex cleaves C4 and C2 much like activated C1

  11. Biological Effects of C Activation • Inflammation • C3a, C5a • Opsonization • C3b • Cell lysis • Membrane attack complex (MAC) C5b-C9

  12. Cell Receptors for C • CR1 • Macrophages, neutrophils • Binding of immune complexes • CR3/CR4 • Macrophages, neutrophils • Binding of immune complexes; enhanced phagocytosis

  13. Regulation of C • Pre C3 convertase • C1 inhibitor • C4b binding protein • Factor 1 • Post C3 convertase • Factor H • DAF • At level of MAC • S protein • MIRL

  14. C Deficiencies • C3 deficiency • Very severe • Other deficiencies in C components or inhibitors

More Related