, also called an antibody
, is a protein
that binds susbtances to eliminate or neutralize them. Most of immunoglobulins are in the blood, but also in the lining of the respiratory tract and the gastrointestinal tract.
Immunoglobulins are produced with small variations that allow them to bind the millions of different microbes. There are 5 types; igg, igm, iga, IgD and ige.