IMMUNOLOGY - LECTURE  SEVEN 

  IMMUNOGLOBULINS: ANTIGEN-ANTIBODY REACTIONS 

  TESTS FOR ANTIGEN-ANTIBODY REACTIONS 

TOPIC: Immunoglobulins: Ag-Ab Reactions Lecture # 8

Tests for Antigen-Antibody Reactions Lecture # 9

FACULTY:

Office: Bldg. #2, Rm. B19

Phone: 733-3281

Email: MAYER@MED.SC.EDU

TEACHING OBJECTIVES:

1. To describe the nature of Ag-Ab reactions

2. To compare and contrast antibody affinity and avidity

3. To delineate the basis for antibody specificity and cross reactivity

4. To discuss the principles of commonly used tests for antigen/antibody reactions

 

REQUIRED READING:

Roitt et al. Immunology, 5th Ed., pp 107-113, Chpt. 29

KEY WORDS:

Affinity, Avidity, Specificity, Cross reactivity, Agglutination, Hemagglutination, Agglutinin, Titer, Prozone, Passive hemagglutination, Direct Coomb's test, Indirect Coomb's test, Hemagglutination inhibition, Precipitin, Equivalence point, Equivalence zone, Zone of antibody excess, Zone of antigen excess, Ouchterlony, Line of identity, Line of nonidentity, Line of partial identity, Radial immunodiffusion, Immunoelectrophoresis, Rocket immunoelectrophoresis, Countercurrent immunoelectrophoresis, Radioimmunoassay, Enzyme linked immunosorbent assay, Competitive RIA/ELISA, Noncompetitive RIA/ELISA, Western blotting, Immunofluorescence, Immunoenzyme staining, Immunoelectron microscopy, Complement fixation

IMMUNOGLOBULINS: AG-AB REACTIONS

I. NATURE OF AG-AB REACTIONS

 

A. Lock and Key Concept - The combining site of an antibody is located in the Fab portion of the molecule and is constructed from the hypervariable regions of the heavy and light chains. X-Ray crystallography studies of antigens and antibodies interacting shows that the antigenic determinant nestles in a cleft formed by the combining site of the antibody as illustrated in Figure 1. Thus, our concept of Ag-Ab reactions is one of a key (i.e. the Ag) which fits into a lock (i.e. the Ab).