5 vials, $29

Immunoglobulin (Ig), also known as an antibody (Ab), is a large Y-shaped protein produced by B-cells that is used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, called an antigen. Each tip of the "Y" of an antibody contains a paratope (a structure analogous to a lock) that is specific for one particular epitope (similarly analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can tag a microbe or an infected cell for attack by other parts of the immune system, or can neutralize its target directly (for example, by blocking a part of a microbe that is essential for its invasion and survival). The production of antibodies is the main function of the humoral immune system.

The five immunoglobulin or antibodies involved in the immune system.

IG 01 IgA
Found in mucosal areas, such as the gut, respiratory tract and urogenital tract, and prevents colonization by pathogens. Also found in saliva, tears, and breast milk.

IG 02 IgD
Functions mainly as an antigen receptor on B cells that have not been exposed to antigens. Has been shown to activate basophils and mast cells to produce antimicrobial factors.

IG 03 IgE
Binds to allergens and triggers histamine release from mast cells and basophils, and is involved in allergy. Also protects against parasitic worms.

IG 04 IgG
Provides the majority of antibody-based immunity against invading pathogens. The only antibody capable of crossing the placenta to give passive immunity to the foetus.

IG 05 IgM
Eliminates pathogens in the early stages of B cell mediated (humoral) immunity before there is sufficient IgG