The detection of phytomitogen-induced changes in human lymphocyte surfaces by laser Doppler spectroscopy

The changes in electrophoretic mobility and isoelectric point produced by incubating human peripheral blood lymphocytes with phytohemagglutinin (PHA) and concanavalin A (Con A) have been characterized by laser Doppler spectroscopy. The results extend and partially confirm older observations made by classical procedures. Incubation with either agent for 90 min at 37 degrees C resulted in stable and reproducible decreases in electrophoretic mobility, and increases in the isoelectric point. The incubation conditions used are known to permit primary attachment of the phytomitogen, capping and endocytosis; nevertheless, at least in the case of Con A, washing the cells with a specific inhibitor for Con A binding, methyl-alpha-D-glucoside (MAG), resulted in complete reversal of the electrokinetic changes, showing that the underlying changes in cell surface constitution detected under these conditions are solely due to reversibly bound Con A. The results suggest that laser Doppler spectroscopic changes could provide a direct assay for specific binding to immunocompetent cell surfaces.