^lgB25⁺ cells induce long lasting T-cell division arrest. (A) T cells were stimulated alone (rhombus), with unstimulated B cells (square), ^smB25⁻ cells (cross), and ^lgB25⁺ cells (triangle) as usual in presence of cCD3 and IL-2. Data are expressed as mean plus or minus SEM of triplicates from 1 representative experiment of at least 3. (B) T-cell division after 3 and 6 days, measured by PKH-26 dilution. M1 relates to 100% PKH-26–positive cells at day 0. (C) MLR with autologous B and T cells (each 25 000) and allogeneic irradiated PBMCs (50 000) in presence of IL-2. Data are expressed as mean plus or minus SEM of triplicates from 1 representative experiment of at least 3 (symbols as in panel A)