Phytohemagglutinin-induced change in the distribution of acidic sugars in surface membrane of lymphoid cells and blocking of the radiation effect

Abstract

Cell electrophoretic mobilities (EPM) of cultured lymphoblastoid cells were measured after removal of acidic sugars to investigate whether the localization of these acidic sugars was altered by the action of phytohaemagglutinin (PHA). After treatment with neuraminidase or hyaluronidase, the EPM of control cells decreased 50.1 and 0.3%, while that of PHA-treated cells decreased 25.2 and 39.0%, respectively. These results suggest that hyaluronic acid appeared at the periphery of the cell surface in place of some sialic acid after incubation with PHA. The change became evident after 10 min incubation with PHA and reached its maximum after 20 min at 37 °C, but no change was observed at 4 °C. The EPM decreased with time after X-irradiation, and reached a minimum value after 4 h. The addition of PHA to culture before irradiation completely blocked the X-ray-mediated reduction in EPM. PHA administration after irradiation stopped further EPM reduction. These results seem to suggest a rapid rearrangement of membrane molecules linking with the receptors and acidic sugars induced by PHA, and blocking of further conformation change by X-irradiation.