Immunoglobulins

Question 1

IgG

Answer 1

75%
Monomer 
2 epitope binding sites
Enhances phagocytosis of bacteria and viruses
Half life 7-23 days

Question 2

IgG Fc

Answer 2

Activate classics component pathway
Bind to macrophage and neutrophils for enhanced phagocytosis
Bind to No cells for antibody dependent cytotoxicity
Cross the placenta
-> NB the only class of antibody which can cross the placenta to the feta circulation

Question 3

IgA

Answer 3

15%
Half life 5days
Mainly in body secretions as secretory IgA - protects internal body surfaces exposed to environment by blocking the attachment of bacteria and viruses to mucous membranes
Made in mucosal associated lymphoid tissues (MALT)
Diner of 2x Y shaped molecules, 4 epitope binding sites
Can activate alternative pathway

Question 4

IgA Fc

Answer 4

Binds to components of mucous and contributes to the ability of mucous to trap microbes

Question 5

IgM

Answer 5

10%
First antibody produced
Half life 5days
Pentamer, 10 epitope binding sites

Question 6

IgM Fc

Answer 6

Activate classical complement pathway (most efficient)

Question 7

IgM monomeric form

Answer 7

On surface of B-lymphocytes as B-cell receptors or sIg

Question 8

IgD

Answer 8

1%
Monomer, 2 epitope binding sites
On surface of B lymphocytes as B cell receptor if sIg (control activation and suppression)
May have a role in eliminating B lymphocytes generating self reactive antibodies

Question 9

IgE

Answer 9

0.002%
Half life 2 days
Monomer, 2 epitope binding sites
Response to parasitic worms and arthropods and allergens
Promotes inflammation enabling IgG, complement proteins and leukocytes to enter tissues

Question 10

IgE Fc

Answer 10

Bind to mast cells and basophils where mediates allergic reactions
Cross linking of cell bound IgE by antigen triggers release of vasodilators
Can bind eosinophils enabling opsonisation