Antibodies

Question 1

What are antibodies?

Answer 1

Antibodies are proteins produced by the body’s immune system in response to a foreign substance?

Question 2

What is an antigen?

Answer 2

A foreign substance

Question 3

Describe the structure of antibodies.

Answer 3

They are Immunoglobulin proteins (Ig)

Question 4

What produces antibodies?

Answer 4

Plasma cells

Question 5

What do antibodies do?

Answer 5

They didn’t fight infection

Question 6

How do antibodies fight infection?

Answer 6

They neutralise pathogenic micro-organisms

Question 7

Where are antibodies found?

Answer 7

They are found in blood and body fluids and on B lymphocyte cell surfaces

Question 8

What do memory cells do?

Answer 8

They are able to be activated to produce antibody when the individual is exposed to the antigen again

Question 9

What is an epitope?

Answer 9

The smallest part of the antigen to which an antibody can be produced

Question 10

Give an example of an antigen.

Answer 10

The Hepatitis B virus

Question 11

What part of the Hepatitis B virus causes the production of an antibody?
(2)

Answer 11

Core proteins or surface proteins

Question 12

What are antibodies composed of?

Answer 12

Heavy chains and light chains

Question 13

What is found at the tip of the chains of an antibody?

Answer 13

The variable region

Question 14

What is a variable region?

Answer 14

Its specific for binding to the specific antigen to which it has been produced

Question 15

How many human antibodies are there?

Answer 15

Five

Question 16

What are the five human antibodies?

Answer 16

IgM
IgA
IgD
IgG
IgE

Question 17

What is the pneumonic for remembering the five human antibodies?

Answer 17

MADGE

Question 18

What does IgG do?

Answer 18

It has an important role in immunity to pathogens

Question 19

How many subtypes are there of IgG?

Answer 19

Four

Question 20

What does IgD do?

Answer 20

The function is unclear but it is found on B cells

Question 21

What does IgE do?

2

Answer 21

It binds to allergens

Triggers histamine release from mast cells

Question 22

Describe the structure of IgG, IgD, IgE.

Answer 22

Monomer Ig

Question 23

Which Immunoglobulins are monomers?

Answer 23

IgG

IgD

IgE

Question 24

Describe the structure of IgA.

Answer 24

Dimer structure

Question 25

What is a dimer structure?

Answer 25

Two antibody molecules

Question 26

Where is IgA found?

Answer 26

Found secreted in saliva, tears, breast milk and mucosal surfaces (gut, respiratory and urinary tract)

Question 27

What is special about the structure of IgA?

Answer 27

It has a j chain

Question 28

What is the function of a J chain?

Answer 28

It is the secretory component of IgA

Question 29

What is the structure of IgM?

Answer 29

Pentameric structure

Question 30

How many Ig are in a pentameric structure?

Answer 30

5 Ig

Question 31

When is IgM used?

Answer 31

Usually occurs as a response to foreign antigen, prior to IgG

Question 32

How are antibodies used in electrophoresis? | 2

Answer 32

Raised Ig level in some diseases e.g. IgA raised in alcoholic hepatitis Deficiency of Ig in some immune disorders e.g. hypo-gammaglobulinaemia results in low levels of all Ig isotypes

Question 33

What does ELISA stand for?

Answer 33

Enzyme-linked ImmunoSorbent Assay ELISA

Question 34

Explain how an ELISA works. | 3

Answer 34

Use microtitre plate and capture antigen in well Antibody (with enzyme attached) added to this well Enzyme-conjugated antibody binds, the enzyme reacts with a substrate to create a colour at site of positives

Question 35

How can antibodies be used to detect auto-immune diseases?

Answer 35

In autoimmune conditions your body can produce auto-antibodies which can be detected

Question 36

Give four example of auto-antibodies.

Answer 36

Anti-nuclear antibodies Anti collagen Anti-smooth muscle Anti mitochondrial

Question 37

How can antibodies be used in Transfusion Science Laboratories?

Answer 37

antibodies are used to determines ones blood type e.g. blood group O have antibody to blood group A and blood group B