Antigen-Antibody Interactions : principles and Applications 미생물학교실 권 형 주

Strength of Ag-Ab interactions Ag + Ab Ag-Ab k1k1 K -1 Affinity: strength of the interaction between an antigen and an antibody Ka : association constant, affinity constant

Determination of antibody affinity by equilibrium dialysis

K a = [Ab-Ag]/[Ab][Ag]= r c(n-r) r= the ratio of the concentration of bound ligand c= the concentration of free ligand n= the number of binding sites per antibody molecule = valency r c = K a n-Kar Scatchard equation Avidity : the strength of multiple interaction between a multivalent antibody and antigen Affinity : Low High Avidity : High Low Valence : High Low IgM IgG

Cross-reactivity ABO blood-group antigens : antigen (glycolipids) on RBC - Difference in the terminal residues of the sugars Blood group antibodies - elicited by microbial antigens Streptococcus pyrogenes M protein Ab -- cross-react with myocardinal and skeletal muscle protein -  Autoimmune diseases Vaccines : Cowpox---smallpox express cross-reacting epitopes

Surface Plasmon Resonance (SPR)

Precipitation reactions Immunoelectrophoresis of an antigen mixture

Agglutination reactions Hemagglutination - Hemagglutination is used in blood typing - Bacterial agglutination is used to diagnose infection - Passive agglutination is useful with soluble antigens : Antigen-coated RBC - soluble Ag with RBC treated with tanic acid or chromium chloride Radioimmunoassay

Enzyme-Linked Immunosorbent Assay (ELISA)

ELISPOT assay Western Blotting

Immunoprecipitation Immunofluorescence

Flow Cytometry and Fluorescence Flow Cytometry and Leukemia Typing