The components of the heteropolymeric immunoglobulin molecules. There are five groups of heavy chains, each characteristic of a specific class of immunoglobulin: gamma (IgG), mu (IgM), epsilon (IgE), alpha (IgA), and delta (IgD). The genes encoding all the heavy immunoglobulin chains are located on human chromosome 14. The constant region of each heavy chain makes up about three-fourths of the molecule, and the gene segments encoding the constant regions are arranged in the sequence mu, delta, gamma, epsilon, and alpha in both humans and mice. There are two groups of light chains: kappa chains, encoded by gene segments on human chromosome 2, and lambda chains, encoded by gene segments on chromosome 22. See immunoglobulin genes.
Subjects: Genetics and Genomics.