Glutathione transferase activities of cultured human lymphocytes

We have detected glutathione transferase (GST) activity towards 1-chloro-2,4-dinitrobenzene (CDNB) and benzo[a]-pyrene 4,5-oxide (BPO) in freshly isolated peripheral lymphocytes, phytohaemagglutinin (PHA)-stimulated lymphocytes, interleukin-2 (IL-2)-dependent T-cells and lymphoblastoid B-cell lines. The detection of conjugating activity with BPO implies the expression of a neutral, 'mu-like' GST form by both resting and cultured lymphocytes. In a sample of 12 unrelated individuals, BPO conjugating activity of freshly isolated lymphocytes showed a polymorphic distribution. In comparison with freshly isolated cells, BPO activity was increased 2- to 5-fold in IL-2-dependent T-cells and 4- to 10-fold in B-cell lines. The CDNB activity of T-cells was not significantly different to that of freshly isolated cells (P greater than 0.05) but activity in B-cell lines showed a significant increase (P less than 0.01). These data indicate that measurement of BPO activity in freshly isolated lymphocytes may allow the study of the human GST-mu polymorphism. However, IL-2-dependent culture of T-cells or viral immortalization of resting lymphocytes appears to cause the activation or induction of a GST form or forms which conjugate BPO efficiently. In the T-cells this effect may be mediated through addition of IL-2 to the culture since PHA treatment alone did not elevate activity.