1. Chapter 6 Ag-Ab Interactions

2. Nature of the Ag-Ab interaction Immunological assays

3. 4 types of noncovalent forces

4. Affinity The strength of the total noncovalent interactions between a single Ag-binding site on an Ab and a single epitope is the affinity of the Ab for that epitope. Avidity The strength of multiple interactions between a multivalent Ab and Ag is called the avidity. Example: secreted pentameric IgM often has a lower affinity than IgG, but the high avidity of IgM, resulting from its higher valence, enables it to bind Ag effectively.

5. Immunological Assays 1. Precipitation 2. Agglutination 3. Radioimmunoassay 4. Enzyme-linked Immunosorbent Assay 5. Western Blotting 6. Immunofluorescence 7. Flow Cytometry and Fluorescence 8. Immunoelectron Microscopy

6. Precipitation Reactions: Precipitation in fluids Precipitation in gels - radial immunodiffusion (Mancini method) - double immunodiffusion (Ouchterlony method) Immunoelectrophoresis

7. Precipitation Reactions

8. Lattice Formation ( 格子 )

10. Double Immunodiffusion (Ouchterlony method)

14. Immunoelectrophoresis

15. Agglutination Reactions: Hemagglutination Bacterial Agglutination Passive Agglutination Agglutination Inhibition

16. Hemagglutination Agglutination No Agglutination No Ab

17. Agglutination Inhibition

18. Solid-phase Radioimmunoassay (RIA)

20. Enzyme-linked Immunosorbent Assay (ELISA): - Indirect ELISA - Sandwich ELISA - Competitive ELISA - Chemiluminescence

24. Elispot Assay

25. Western Blotting

26. Immunofluorescence

28. Flow Cytometry FACS: Fluoresence-activated Cell sorter

30. Immunoelectron microscopy