Fractionation of human lymphocytes with plant lectins. I. Structural and functional characteristics of lymphocyte subclasses isolated by an affinity technique using Lens culinaris lectin

We have fractionated human peripheral blood lymphocytes (PBL) into subclasses with an affinity technique that takes advantage of the specific interaction between the plant lectin, Lens culinaris agglutinin (Lentil-PHA), and its cell surface receptors. PBL were incubated in plastic tubes or petri dishes coated with a gelatin layer to which lentil-PHA had been 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 to 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 × 10⁶ lentil-PHA molecules per cell, adherent cells bound more (3.7 × 10⁶/cell), and nonadherent cells bound less (1.1 × 10⁶/cell) lentil-PHA. By contrast, 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 whereas the two groups responded the same to stimulation by the leukoagglutinin from Ph. vulgaris. The data indicate that plant lectins may be used to isolate PBL subclasses with different structural and functional properties.