1. IMMUNOGLOBULIN STRUCTURE AND FUNCTION
March 19, 2009
10:00-11:00

2. IMMUNOGLOBULIN AND HUMORAL IMMUNITY
Two functions:
1)mIg Is the B cell antigen recognition receptor
2) secreted Ig is the effector protein for adaptive humoral immune responses

3. IMMUNOGLOBULINS HAVE 4 POLYPEPTIDE CHAINS
2 Identical H(eavy) chains
2 Identical L(ight) chains

4. HEAVY AND LIGHT CHAINS HAVE VARIABLE AND CONSTANT REGIONS

5. ANTIBODY MOLECULES HAVE GLOBULAR REGIONS
The globular regions are separated by a “flexible” hinge
The globular regions contain globular domains

6. THE STRUCTURE OF THE DOMAINS PROVIDES STABILITY
Domains are approximately 110 amino acids
Amino acids are aligned in b sheets
V and C are slightly different

7. THE DIFFERENT CLASSES OF ANTIBODY
There are two types of L chain: k and l
There are 5 types of H chain: g, m, d, a, e
A complete antibody molecule has 2 identical light chains
and 2 identical heavy chains

8. ANTIBODY MOLECULES CAN BE CLEAVED BY PROTEOLYTIC ENZYMES

9. ANTIGEN BINDING SITES ARE HYPERVARIABLE

10. ANTIBODIES BIND TO ANTIGENS
IMMUNOGEN
A molecule that elicits an immune response
EPITOPE
The part of an antigen to which an antibody binds

11. CARRIER HAPTEN HAPTEN-CARRIER NOT ALL ANTIGENS ARE IMMUNOGENIC Epitope

12. AN ANTIBODY BINDS EPITOPES ON A VIRAL PARTICLE

13. TWO TYPES OF EPITOPE

14. ANTIGEN BINDING SITES HAVE DIFFERENT SHAPES

15. MOST NATURAL ANTIGENS ARE MULTIVALENT

16. THE INTERACTION BETWEEN ANTIBODIES AND MULTIVALENT
ANTIGENS LEADS TO COMPLEX FORMATION
Trapped complexes cause inflammation

17. ANTIBODIES ARE CLINICAL TOOLS

18. PRODUCTION OF MONOCLONAL ANTIBODIES

19. RIA AND ELISA ARE USED TO MEASURE LEVELS OF SUBSTANCES
IN SERUM
Hormone levels
Drug levels
Viral levels

20. APPLICATIONS
DIAGNOSTIC
Measuring protein levels:
ELISA
Identification and Characterization of Antigens:
Immunoprecipitation and Western Blots
Characterization of Cells and Cell Separation:
Fluorescent labeling and Flow Cytometry
Localization of antigen in tissue:
Immunohistochemistry
THERAPEUTIC
Treatment of inflammatory disease with anti-cytokine
Treatment of cancer with toxin conjugated antibodies
Passive immunization

21. THERAPEUTIC MONOCLONAL ANTIBODIES
Schwartz, NEJM 348;