Lymphocyte electrophoresis as an indicator of modulation of concanavalin A-induced suppressor T-cells in vivo by anti-cancer drugs.

We have previously reported that concanavalin A (Con A)-induced suppressor T-cells in vivo are located in the lower electrophoretic mobility (EPM) zone as judged by the ratio of low mobility T-cells to high mobility T-cells (LMT/HMT ratio) in terms of lymphocyte electrophoresis, and that the administration of 5-fluorouracil (5-FU) eliminates their suppressor activity as assayed by Con A-induced lymphocyte blastogenesis in vitro. The current study was undertaken to clarify the relation between changes in EPM and suppressor activity of Con A-induced suppressor T-cells by the administration of antitumor drugs such as cyclophosphamide (CY) and 5-FU when assayed by production of anti-sheep red blood cell antibody in vitro. The pretreatment with 5-FU, but not CY, abrogated the suppressor activity of Con A-induced T-cells followed by restoration of the LMT/HMT ratio of Con A-induced T-cells to that of normal T-cells. These finding suggest that lymphocyte electrophoresis can be applied to an assay for screening immunomodulating agents in Con A-induced suppressor T-cells.