Effect of cyclosporin A on suppressor T cells

The effect of cyclosporin A (CsA) on suppressor T cells (Ts) was evaluated by in vitro incubation with afferent-phase Ts (Ts-aff) and efferent-phase Ts (Ts-eff). 2,4-Dinitro-1-fluorobenzene (DNFB) and hen egg-white lysozyme (HEL) were used as antigens. Both Ts-aff and Ts-eff were resistant to high- and low-dose CsA treatments. However, T cells associated with delayed type hypersensitivity (DTH) [TDTH] to DNFB or HEL were sensitive to these CsA treatments. These results indicate that the effect of CsA treatment on contact sensitivity and DTH influences TDTH and not Ts.