immune system

IgA

Secreted in breast milk and tears

Resistant to digestion and can activate the compliment pathway when aggregated

IgD

Expressed on the surface of mature B cells

Works with IgM in B cell development

found in very low levels in serum and does not activate the compliment pathway

IgE

Expressed on the surface of mature B cells

Least abundant Ig in serum and does not activate the compliment pathway

Allergic reactions

IgG

Expressed on the surface of mature B cells

Most prevalent Ig in serum

Pass from mother to fetus to transfer immunity

IgM

Expressed on the surface of immature and mature B cells as monomers

Third most abundant

First human immunoglobulin made by a fetus and virgin B cells

Strong compliment activator and agglutinator

Type 1

anaphylaxis, allergies, asthma

Type 2

blood group incompatibility, pernicious anemia, myasthenia gravis

Type 3

systemic lupus erythematosus, rheumatoid arthritis, serum sickness, rheumatic fever

Type 4

infection reactions, contact dermatitis, graft rejection