Shafqat

Where are antibodies found?

1. Free in serum

2. Free in secretions (mucous, milk, saliva, tears)

3. Surface of cells

Function of Antibodies

To binds to antigens with a complimentary shape and neutralise them.

Basic Antibody Structure

2 light chains

2 heavy chains

2 antigen binding sites

2 types of light chain

Kappa and Lambda

5 types of heavy chain

-Gamma

-Delta

-Epsilon

-Alpha

-Mu

How is diversity in an antibody produced

Through rearrangement of genes in the variable regionWhat

What binds chains together

disulphide bonds

what is the function of the hinge region

provide flexibility when binding to the antigen

What is a CDR

Complimentary Determining Regions

-Binds to antigens

Structure of Variable Region

Forms a beta-sheet structure to hold hypervariable regions in place

Stability of variable region?

More stable amino acid sequence than CDR

CDR interactions with antigen

1. Hydrogen bonding

2. Electrostatic Forces

3. Van Der Waals Forces

4. Hydrophobic Forces

5 antibody classes

1. IgG

2. IgD

3. IgE

4. IgA

5. IgM

Type of chains in each

IgA has alpha chains, IgD has delta chains etc.

IgA Structure

Dimer of 2 antibodies joined by a J polypeptide chain

IgM Structure

Pentamer of 5 Ig molecules with Mu chains

Functions of Antibodies

1. Immobilisation

2. Agglutination

3. Neutralisation

4. Opsonisation

5. Activation of Complement

Immobilisation of Bacteria (Antibodies)

Antibodies specific to flagella and cilia cause them to clump , preventing movement