STIMULATION OF LEUKEMIC-CELLS FROM ADULT T-CELL LEUKEMIA PATIENTS WITH BACTERIAL SUPERANTIGENS

Bacterial superantigens stimulate T cells in a manner;hat is restricte d to the VP of the T-cell receptor. We examined the ability of adult T -cell leukaemia (ATL) cells to respond to these superantigens. Mononuc lear cells from 10 patients were cultured with staphylococcal enteroto xin A (SEA), staphylococcal enterotoxin B (SEE) or toxic shock syndrom e toxin-1 (TSST-1), and their response was determined by MTT assay and H-3-thymidine incorporation assay. Cells from six patients showed a s pecific response to a single superantigen. In two cases the cells resp onded to TSST-1 and bore V beta 2, the known target of TSST-1. In thre e cases the cells responded to SEA with one bearing V beta 9, a target of SEA, and one bearing V beta 16. In one case the cells responded to SEE. Most of the cells which proliferated in response to superantigen s were determined genetically to be leukaemic. The response to TSST-1 was inhibited by anti-V beta 2 antibody. The responding cells showed a strongly enhancement expression of interleukin-2 receptor. These find ings indicate that leukaemic cells from a proportion of ATL patients h ave an ability to respond to T-cell receptor-dependent superantigens, This suggests that bacterial infection in such patients may contribute to the expansion of Am cells.