LOCATION AND EXPRESSION OF IDIOTYPIC DETERMINANTS IN THE IMMUNOGLOBULIN VARIABLE REGION .2. CHAIN LOCATION OF VARIABLE REGION DETERMINANTS

Both myeloma protein 460 and myeloma protein 315 each exhibit two sets of idiotypic determinants. A 'private' determinant set which distinguishes protein 460 and protein 315 from each other, and a common or 'public' set of idiotypic determinants which are shared by proteins 315 and 460 and which distinguish these two proteins from many other mouse IgA myeloma proteins. One other mouse myeloma protein which shares the 'public' idiotype is myeloma protein S.23 which has heavy chain amino acid sequences which resemble in part those of protein 460. Heavy-light chain recombinant molecules of these three proteins were made. The amino acids constituting both the public and private idiotypic markers were located on the heavy chains. The public idiotypic is expressed in recombinatant molecules no matter which light chains were associated with the heavy chains. Antigenic expression of private idiotypes, however, depended on the type of light chain which was present. Modulation of antigenic expression of structural idiotypic determinants by associated chains must be considered when idiotypic determinants are used as genetic markers. © 1979.