Antibodies (NG)

Question 1

What are Antibodies

Answer 1

Family of glycoproteins
Also known as immunoglobulins
Y-shaped protein
Identify and neutralise foreign objects
Viruses, bacteria etc
Targets are known as antigens
Recognise unique part of antigen – epitope

Question 2

Structure

Answer 2

• membrane bound/soluble
• Basic units
• 2 large heavy chains
• 2 small light chains
• stable hetero tetramer
• Extensive non-covalent and covalent interactions
• Isotopes/several classes of antibody

Question 3

Specificity

Answer 3

• Hypervariable region
• Allows for approx 10^9 different antibodies
• A B-lymphocyte can have 50,000-100,000 antibodies on surface
• An antigen may present thousands of unique epitopes

Question 4

Classes of antigens

Answer 4

IgG Monomer (80% free antibody) - Primary and secondary immune response

IgM Pentamer - (10% free plasma) - B-cell antigen receptor, primary immune response

IgD Monomer - <1%. Binds mast cells and basophils Inflammation and allergy.

Question 5

Antibody Functions

Answer 5

Activated B cells differentiate

• Plasma cells secrete soluble antibody
• Memory cells survive to provide immune memory

Passive immunisation at prenatal and neonatal stage

Antibodies exist freely in blood stream
-part of humoral immune system

Circulating antibodies produced by clonal B cells
-Specifically respond to one antigen e.g viral protein

Contribute to immunity in three ways

• Prevent pathogens entering damaged cells
• Stimulate removal by phagocytes by coating
• Trigger other immune response

Question 6

Antibody production

Answer 6

Specific antibodies are produced by injecting an antigen into a mammal.

Blood isolated from these animals contain polyclonal antibodies

Antibody secreting lymphocytes can be isolated and immotalised by produce hybridomas

Single hybridomas are isolated to generate cell clones

Cell clones all produce the same antibody

These antibodies are called monoclonal antibodies

Question 7

Hybridoma production

Answer 7

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