Immunoglobulin

Question 1

What are immunoglobulins?

Answer 1

Are antibodies that are Y shaped glycoproteins produced by B cells

Question 2

What is the main function of immunoglobulins?

Answer 2

They bind specific antigens to help eliminate pathogens

Question 3

What are the five main classes of ummunoglobulins?

Answer 3

IgM, IgG, IgA, IgE and IgD

Question 4

When is IgM produced during an immune repsonse?

Answer 4

IgM is the first antibody produced in an immune response

Question 5

What is the structure of secreted IgM?

Answer 5

It is a pentamer joined by a J chain (kinda star shaped)

Question 6

What is the function of IgM on B cells?

Answer 6

It acts as a B cell receptor (BCR) in monomeric form

Question 7

What are the main functions of IgM?

Answer 7

Complement activation and pathogen agglutination

Question 8

What is the most abundant antibody in serum?

Answer 8

IgG

Question 9

What is the structure of IgG?

Answer 9

Is a monomer

Question 10

How long does IgG last in the blood?

Answer 10

It has a long half life of around 23 days

Question 11

What are key functions of IgG?

Answer 11

• Neutralisation
• Opsonisation
• Complement activation
• Antibody-dependent cellular cytotoxicity

Question 12

What immune response is IgG mainly involved in?

Answer 12

Secondary immune response - memory response

Question 13

What role does IgG play in pregnancy?

Answer 13

It crosses the placenta to provide passive immunity to the featus

Question 14

Where is IgA mainly found?

Answer 14

In mucosal areas and secretions

Question 15

What is the structure of secretory IgA?

Answer 15

Is a dimer joined by a J chain and secretory component

Question 16

What is the main function of IgA?

Answer 16

Mucosal protection by neutralising pathogens and preventing adherence

Question 17

How does IgA protect newborns?

Answer 17

Through breast milk providing mucosal immunity

Question 18

What is the structure of IgE?

Answer 18

Is a monomer

Question 19

What cells does IgE bind to?

Answer 19

Mast cells and basophils via high affinity Fc receptors

Question 20

What happens when allergens cross link IgE?

Answer 20

Mast cells degranulate releasing histamines and causing allergic reactions

Question 21

What is IgE’s main role in immunity?

Answer 21

Defence against parasitic worms and involvement in allergies

Question 22

What clinical conditions show elevated IgE?

Answer 22

Allergies and parasitic infections

Question 23

Which immunoglobulin class activated complement best?

Answer 23

IgM followed by IgG

Question 24

Which immunoglobulins act as B cell receptors?

Answer 24

IgM and IgD

Question 25

Which immunoglobulins provide passive immunity to newborns?

Answer 25

IgG and IgA

Question 26

Which immunoglobulin is involved in Type I hypersensitivity reactions?

Answer 26

IgE