A comparison of the electrokinetic properties of metastasizing and non-metastasizing forms of a hamster lymphosarcoma.

Metastasizing (ML) and non-metastasizing (NML) forms of a hamster lymphosarcoma were investigated for possible differences in the cell surface properties using isoelectric equilibrium analysis and cytopherometry. ML cells were found to have a higher isoelectric point (pI) and therefore a lower net negative charge density on their surface than the NML cells. On the contrary, ML cells showed a greater electrophoretic mobility than NML cells. When pH mobility curves were constructed for the two tumour types, the curves crossed over at pH 4.8. The isoelectrophoretic points (pIE) extrapolated from these curves gave a pIE for ML cells which was higher than that of NML cells; thus, consistent with their true pI values. Furthermore, the isoelectric data showed that the two tumour types possessed similar negative charge densities at pH 4.8 which confirmed the crossover phenomenon noticed with the pH mobility curves. It is suggested that the contradictory observations may be due to differences in the depths of the zones of the cell surface probed by the two electrokinetic methods, and that in ML cells a greater proportion of a cationic groups occur at a depth of between 30 and 60 Angstrom zone adjacent to this plane. The isoelectric data also suggest that the cationic groups of NML cells are more basic than those of the ML cells.