There are five classes of antibody. 1) <span>IgA (immunoglobin A) 2) IgD (immunoglobin D) 3) IgE (immunoglobin E) 4) IgG (immunoglobin G) <span>5) IgM (immunoglobin M)
They form Y shaped antibodies. The crystallized fragment is the stalk of the Y shaped antibodies. The bond formed by this stalk will determine the form of the antibody. One Y is called monomer, two connected Ys are called dimers, and 5 connected Ys are called pentamers.</span></span>