There are five classes of mammalian immunoglobulins: IgA, IgD, IgE, IgG, and IgM. In mice, the IgG class is further divided into four subclasses: IgG1, IgG2a/ IgG2c (strain specific), IgG2b, and IgG3.The general immunoglobulin structure is described as two heavy and two light chain (H2L2) polypeptides linked together by disulfide bridges of cysteine residues. Mouse IgE, also known as reaginic antibody, exists in serum as a 4-chain monomer of 185–200 kDa. Like IgM, the IgE monomers contain a