FRACTIONATION OF HUMAN-LYMPHOCYTES WITH PLANT-LECTINS .1. STRUCTURAL AND FUNCTIONAL-CHARACTERISTICS OF LYMPHOCYTE SUBCLASSES ISOLATED BY AN AFFINITY TECHNIQUE USING LENS-CULINARIS LECTIN

Human peripheral blood lymphocytes (PBL) were fractionated into subclasses with an affinity technique that takes advantage of the specific interaction between L. culinaris agglutinin (lentil-PHA [phytohemagglutinin]) and its cell surface receptors. PBL were incubated in plastic tubes or petri dishes coated with a gelatin layer to which lentil-PHA was coupled using a water soluble carbodiimide compound. Adherent cells were recovered by melting the gelatin and bound lectin was removed by exposing the cells to an appropriate sugar hapten. Approximately 25-50% of PBL specifically adhered to gelatin-coated tubes derivatized with lentil-PHA. Binding studies with 125I-labeled lentil-PHA showed that, compared to unfractionated PBL which bound 2.0 .times. 106 lentil-PHA molecules per cell, adherent cells bound more (3.7 .times. 106/cell) and nonadherent cells bound less (1.1 .times. 106/cell) lentil-PHA. There were no differences among these groups for binding of other plant lectins. When stimulated in vitro by optimal mitogenic concentrations of lentil-PHA, lymphocytes adherent to lentil-PHA responded better than their nonadherent counterparts; the 2 groups responded the same to stimulation by the leukoagglutinin from Phaseolus vulgaris. Plant lectins may be used to isolate PBL subclasses with different structural and functional properties.