Human B-cell mitogenic responsiveness to lectins: The requirement for T cells

Abstract

The mitogenic potential of normal human peripheral blood lymphocyte subpopulations in response to the plant lectins phytohemagglutin, erythroaggluting phytohemagglutinin, leukoagglutinating phytohemagglutinin, and pokeweed mitogen has been examined. Doubly purified B-, Null, and T-cell fractions were used by themselves and in conjunction with small percentages (1 to 10%) of other subpopulations. Purified human B and Null cells were found to be nonreactive. However, when incubated with as little as 1% T cells, significant mitogenic responsiveness by B and Null cells was observed. This helper effect was apparent with both normal and irradiated T cells. It would thus appear that mitogenic responsiveness of unseparated mononuclear cells is predominantly a function of T cells either as responding cells or as necessary helper cells.