Induction of CD25⁺ FoxP3⁺ Treg cells by NHL tumor cells under different conditions. (A) An example of comparable induction with unfractionated splenic cells, CD20⁺ tumor cells, and CD304⁺, CD25⁺–depleted splenic cell suspensions with CD25⁻ PBMCs after 5 days incubation. (B) Increased induction at 96 hours of incubation compared with 36 hours. (C) The effects of separating tumor and PBMC fraction using transwells (n = 4 patients).