The immunoglobulin light chain is the small polypeptide subunit of an antibody (immunoglobulin). A typical antibody is composed of two immunoglobulin (Ig) heavy chains and two Ig light chains. There are two types of light chain in humans: kappa (κ) chain, encoded by the immunoglobulin kappa locus (IGK@) on chromosome 2; lambda (λ) chain, encoded by the immunoglobulin lambda locus (IGL@) on chromosome 22.