Alan Solomon and Carla

The immunochemical demonstration that the Bence Jones protein from the urine of an individual patient with multiple myeloma was antigenically identical to a portion of the homologous serum myeloma protein (1), and the establishment of the chemical and structural similarities between Benee Jones proteins and light polypeptide chains (2, 3) which are common to immunoglobulins of all known classes (4) emphasized the importance of the Bence Jones protein as a source of homogeneous material for studies on immunoglobulin structure and antibody specificity. Two distinct types of immunoglobulin light chains (K or X) were evidenced by immunochemical studies on Benee Jones proteins (1, 5, 6). Although Bence Jones proteins of ~ type share no peptides in common with Bence Jones proteins of X type, comparative analyses of tryptic peptide maps of Bence Jones proteins provided the initial evidence that proteins of the same type have distinctive as well as common peptides (7). Amino acid sequence determinations on Bence Jones proteins (summarized in reference 8) revealed a remarkable primary structure characterized by variancy in the first 107 amino acid residues of the amino terminal half and by constancy in the next 107 amino acid residues of the carboxyl terminal half. Hence, proteins of the same type possess distinctive variant halves but have similar constant halves. Differences and similarities among Bence Jones proteins and isolated light chains within each major type have been evident immunochemically (9-16). Immunochemical comparisons of ~ light chains with antisera developed against n Bence Jones proteins provided evidence for extensive antigenic heterogeneity which was not related either to the Inv (3) or Inv (2) genetic type 1 of the protein (12). Amino acid