Electrophoretic Mobility and N-Acetyl Neuraminic Acid Content of Human Normal and Leukemic Lymphocytes and Granulocytes

Studies have been conducted to determine the electrophoretic mobility and the N-Acetyl Neuraminic Acid (NANA) content of different human leukocyte types. Leukemic granulocytes and lymphocytes do not differ significantly from their normal counterparts in rate of electrophoretic mobility. An absolute comparison between leukemic and normal myeloblasts could not be made; however, populations of leukemic myeloblasts were often similar in mobility to normal immature granulocytes. Immature granulocytes had a significantly higher surface-charge density than PMNGs, and this is due primarily to differences in NANA carboxyl groups contributing to the electro-kinetic surface of the cell. The small lymphocyte has a surface-charge density more similar to that of immature granulocytes and myeloblasts than to that of PMNGs. The surface-dependent behavior of different leukocyte types may be related, in part, to the density or arrangement of NANA molecules at the cell periphery; alternatively, the distribution of surface NANA may be a reflection of other differences in molecular arrangement of the cell membrane which are important in determining functional capacities. Total cellular NANA is greater in the PMNG than the lymphocyte, and this is likely to be a reflection of the larger surface area of external and internal membranes of the PMNG. These data also suggest that the surface area of the PMNG and lymphocyte is not reflected by the assumption of a smooth sphere. Neither total NANA nor neuraminidase-susceptible NANA can be used as an estimate of comparative NANA-dependent surface-charge density which must depend on electrophoretic mobility measurements with and without neuraminidase treatment.