Peanut lectin binding as a marker for activated T-lineage lymphocytes

A series of experiments was undertaken to ascertain the reliability of peanut agglutinin (PNA) binding as a means of distinguishing mouse pre-T cells from other cell types. Normal bone marrow, thymus and spleen cells were stained with graded doses of fluoresceinated lectin (FITC-PNA) and subsequently examined by fluorescence microscopy to determine the number of lectin-binding cells. In addition, the PNA binding properties of mitogenically activated lymphocytes were examined in a similar manner. The results of this study show that PNA binding does not define a fixed population of cells, as the percentage of PNA+ cells detected in normal mouse tissues varied directly with the concentration of PNS used for staining. Nor is PNA able to distinguish between pre-T cells and mature T cells after mitogenic stimulation, both of which are shown to bind PNA. This lectin may , however, have value as a general marker of lymphoid precursors and activated lymphocytes of the T lineage.