Comparison of Normal and CLL Lymphocyte Surface Ig Determinants Using Peroxidase-labeled Antibodies. I. Detection and Quantitation of Light Chain Determinants

Chronic lymphocytic leukemia (CLL) and normal human blood lymphocytes were investigated with regard to their membrane-associated light (L) chains. Peroxidase-labeled anti-kappa or anti-lambda antibodies were used to visualize by light microscopy the cells bearing L chain determinants. In addition, the activity of the enzyme coupled to the antibody was measured spectrophotometricly in order to determine the number of antigenic determinants on each positive cell. The results demonstrated that 16%-25% of lymphocytes from six normal control subjects were positive for kappa chains, and 4%-10% were positive for lambda chains. The average number of antigenic sites on the surface of each positive cell was calculated to be 90,000. Lymphocytes of each of the 14 CLL patients studied carried either kappa or lambda antigenic determinants on their surface, but not both; 50%-70% of the lymphocytes were stained. The average number of antigenic sites per positive CLL was calculated to be 9000. These results confirm previously reported studies indicating that CLL is a monoclonal proliferative disease. In addition, the quantitative results demonstrate that the CLL lymphocyte surface membrane bears, on the average, only 10% of the L chain determinants present on the normal lymphocyte.