Effect of Richinus communis lectins on the membrane fluidity of human peripheral lymphocytes

The mobility of Ricinus communis lectins bound to lymphocyte cell surface was determined by fluorescence polarization of fluorescein-labeled lectins. R. communis hemagglutinin and R. communis toxin have high mobility. Furthermore, the change of membrane fluidity upon binding of the lectins to lymphocytes was measured by fluorescence polarization of fluorescent hydrocarbon embedded in the membrane. The hemagglutinin, the toxin and its binding subunit apparently increased the membrane fluidity. The hemagglutinin was also found to have mitogenic activity against human peripheral lymphocytes.