Saporin-conjugated DC-HIL inhibits proliferation of SD-4⁺ CTCL cells and PBMCs of patients with SS. HuT-78 (A), HH cells (B), or PBMCs from a patient (Pt. 3A) with SS (C) were cultured for 2 days with varying nanomolar concentrations of saporin-conjugated DC-HIL or control saporin in the presence of IL-2. Proliferation of treated cells was measured by ³H-thymidine uptake. The effect of saporin conjugates on proliferation is expressed as a percentage relative to counts per minute taken by untreated cells (at 0nM saporin conjugate).