Fractionation of human lymphocytes with plant lectins. II. Lens culinaris lectin and wheat germ agglutinin identify distinct lymphocyte subclasses

We have fractionated human peripheral blood lymphocytes (PBL) into distinct subclasses based upon differential adherence to the plant lectins wheat germ agglutinin (WGA) and Lens culinaris lectin (lentil-PHA), derivatized to gelatin surfaces in plastic tubes and Petri dishes. Fifteen to forty percent of PBL were adherent to WGA-derivatized gelatin. Binding studies with ¹²⁵I-WGA showed that, compared to unfractionated PBL which bound 31.9 x 10⁶ WGA molecules/cell, adherent cells bound more (44.1 x 10⁶ molecules/cell), and nonadherent cells bound less (20.4 x 10⁶ molecules/cell) WGA. By contrast, there were no differences among these groups for binding of other plant lectins. When lentil-PHA-derivatized gelatin was used, 25 to 50% of PBL were adherent, and, as previously reported, adherent cells bound approximately 4 times as many lentil-PHA molecules as nonadherent cells, whereas there were no differences in binding of other lectins. Sequential fractionation studies indicated that the WGA- and lentil-PHA-selected subclasses were separate groups. The percentage of T and B lymphocytes and macrophages did not differ among the subclasses. WGA-selected and lentil-PHA-selected lymphocyte subpopulations responded differently to stimulation in vitro by a panel of plant mitogens. Human PBL contain a spectrum of cell subclasses with different lectin-binding capacities. These subclasses are functionally unique.