Immunoglobulins

Question 1

Monomer
* Enhance phagocytosis of bacteria and viruses
* Fixes complement and passes to the fetal circulation
* Most abundant isotype in blood serum

Answer 1

IgG

Question 2

Monomer/ dimer
* Found in breast milk and secretions of digestive, respiratory and urogenital tracts
* Provides localized protection on mucous membranes
* Transported across the interior of the cell via transcytosis

Answer 2

IgA

Question 3

Pentamer
* First immunoglobulins to be secreted in response to an infection
* Fixes complement but does not pass to the fetal circulation

Answer 3

IgM

Question 4

Monomer
* Role in immune system largely unknown
* Involved in activation of B cells

Answer 4

IgD

Question 5

Monomer
* Mediates type 1 hypersensitivity reactions
* Synthesised by plasma cells
* Binds to Fc receptors found on the surface of mast cells and basophils
* Provides immunity to parasites such as helminths
* Least abundant isotype in blood serum

Answer 5

IgE