Effect of srhCD40L on proliferation of breast carcinoma cell lines in vitro. After 72 hours, proliferation was assessed by MTT. (▩) srhCD40L, (▧) anti-CD40 MoAb, and (⧫) msIgG1 control. (A) MDA-231, (B) T-47D, (C) BT20, and (D) MCF-7 (CD40⁻) cell line. Incubation with either 1 or 10 μg/mL srhCD40L resulted in significant (P < .001) inhibition of proliferation of the 3 CD40⁺ lines (A, B, and C).