There are two identical long heavy chains and two identical short light chains. The stem of the Y is made only of heavy chains while the arms of the Y are composed of both types of chains. The form of an antibody is like the body of a lobster. Each antibody is specific for a given antigen. Each type of antibody is made by cells from the same clone.
Humans have five different types of antibodies which are given shorthand names.
Each type of antibody serves a particular purpose. IgA Also known as secretory antibody as it is found in tears, saliva and on the surface of mucus membranes. IgD Found on the surface of B cells, it assists B cells in recognizing antigens for which they are specific. IgE Plays a role in allergic reactions. In the presence of antigens IgE triggers WBCs called basophils to release allergy-producing chemicals such as histamine.