Efficacy of G28-5 sFv-PE40 on Ramos xenografted SCID mice and the effect of administration schedule. Ramos xenografted SCID mice treated with G28-5 sFv-PE40 with a schedule of q2dx5 (A), q3dx5 (B), or q4dx5 (C) with a dose of either 0.13 mg/kg (▿) or 0.26 mg/kg (□). Control mice (♦) received no immunotoxin. Animals in (C) received only the 0.26 mg/kg dose.