![STRUCTURE
• All antibodies share a basic structure
• Antibodies are heavy globular plasma
proteins[or]glycoproteins
• The attached glycans are critically important to
the structure and function of the antibody
• Each antibody is heterodiamer with a molecular
weight of approximately 150D](https://image.slidesharecdn.com/antibodieslecture-240229101001-cb833d04/85/ANTIBODIES-STRUCTURE-AND-ITS-FUNCTIONS-3-320.jpg)
![IMMUNOGLOBULIN
DOMAINS
• Antibody is composed of two identical heavy
polypeptide chains and two identical light
chains,bonded via interchain disuIphide[s-s]
linkages
• Each chain is composed of structural domains
called Immunoglobulin domains
• These domains contains about 70-110
aminoacids](https://image.slidesharecdn.com/antibodieslecture-240229101001-cb833d04/85/ANTIBODIES-STRUCTURE-AND-ITS-FUNCTIONS-5-320.jpg)
ANTIBODIES ,STRUCTURE AND ITS FUNCTIONS
- 1. ANTIBODY OR IMMUNOGLOBULIN DR.ZARNAB SATTAR LASHARI SENIOR DEMONSTRATOR
- 2. Definition • Antibody is a large protein ,constitiutes y-gloublin produced by plasma cells • It is used by the immune system to identify and nutralize pathogens such as bacteria and viruses • Antibodies are also called Immunogloublins • The antibody recognizes a unique molecule of the harmful agent called ANTIGEN,via the variable region
- 3. STRUCTURE • All antibodies share a basic structure • Antibodies are heavy globular plasma proteins[or]glycoproteins • The attached glycans are critically important to the structure and function of the antibody • Each antibody is heterodiamer with a molecular weight of approximately 150D
- 5. IMMUNOGLOBULIN DOMAINS • Antibody is composed of two identical heavy polypeptide chains and two identical light chains,bonded via interchain disuIphide[s-s] linkages • Each chain is composed of structural domains called Immunoglobulin domains • These domains contains about 70-110 aminoacids
- 6. HEAVY CHAINS • Five types of heavy chains are present • They are;1)aipha(a) 2)gamma(y) 3)deIta(a) • 4)epsilon 5)mu(g) • Each heavy chain has two regions,one constant region and one variable region • Alpha and gamma chains contains approximately 450 aminoacids, where as mu and epsilon chains have approximately 550 aminoacids
- 7. LIGHT CHAINS • Two types of light chains are present • They are;1)kappa 2)Iambda • All antibodies have one of the two kinds of light chains • A light chain has two successive domains,one constant domain and one variable domain • The approximate length of a light chain is 211-217 aminoacids
- 8. Sites of Immunogloublin Heavy ct›ain Ant1gen binding sites Variable region " on heavy chain Variable regio on light chain Constant region on light chain Constant reg on heavy chaln
- 9. DIFFERENT CLASSES OF ANTIBODIES • There are five classes of antibodies are present • They are;1)IgG 2)IgM 3)IgA • 4)IgD 5)IgE • The antibody classes are named as correspond to their heavy chain types
- 10. 1)IgG • They makes up approximately 80% of the serum Antibodies • They has a half-life of 7-23 days • IgG is a monomer and has 2-epitope binding sites • This is the only class of antibodies that can cross the placenta and enter the fetal circulation
- 11. Functions • Immunity to new born • Neutralisation of Toxins • IgG3 binds to Fc receptor by Phagocytosis
- 12. 2)IgM • They makes up approximately 13% of the serum Antibodies • They has a half-life of about 5 days • Most of the IgM are pentamer and has 10 - epitope binding sites.some are momomer • It is the first immunoglobulin class produced in a primary response to antigen
- 13. functions • Activation of classical pathway • Defence against multivalent antigens • Act as Opsonin
- 14. 3)IgA • They makes up approximately 6% of the serum Antibodies • They has a half-life of approximately 5 days • IgA is a dimer and has 4-epitope binding sites • They found mainly in body secretions such as saliva,mucous,tears,colostrum and milk
- 15. Functions • It as a Seceratory antibody • Effective against virus that causing Influnza • Production to Infant gut
- 16. 4)IgD • They makes up approximately 0.20 /oof the serum Antibodies • IgD is a monomer and has 2-epitope binding sites. • This class antibodies are found on the surface of B-lymphocytes
- 17. Function • B cell activation. • Act a receptor for antigen binding
- 18. 5)IgE • It is very low concentration in blood(17- 450ng/ml). • It contain small percentage of Lympocytes
- 19. Functions • Responsible for Immediate hypersensitivity • Binds to Fc receptor on basophils and mast cells • Release of substance like histamine ,vasoactive mediators