Source:http://linkedlifedata.com/resource/umls/id/C0021008
NCI: The portion of an antibody that is invariant within a class of immunoglobulins. It is comprised of the carboxyl terminal half of both light chains and at least three quarters of each heavy chain starting from the carboxyl terminus and excludes the variable regions of the heavy and light chains.,MSH: The domains of the immunoglobulin molecules that are invariable in their amino acid sequence within any class or subclass of immunoglobulin. They confer biological as well as structural functions to immunoglobulins. One each on both the light chains and the heavy chains comprises the C-terminus half of the IMMUNOGLOBULIN FAB FRAGMENT and two or three of them make up the rest of the heavy chains (all of the IMMUNOGLOBULIN FC FRAGMENT)