Effect of CD40 stimulation on Burkitt lymphoma proliferation in vitro.

Daudi (A,B) and Raji (C) cells were incubated either alone or with log dilutions of srhCD40L or CD40 antibody (SGN-14 clone, mouse IgG1) for 72 hours. Measurement of proliferation was performed using a microculture tetrazolium (MTT) assay as described in “Materials and methods.” Data are presented as the mean with SD. Viability of the cells (D) was assessed using the trypan blue exclusion method. Treatment of Daudi and Raji cells with either CD40L or CD40 antibody (at 10 μg/mL concentration) resulted in a significant (P < .001) decrease in proliferation, as well as a decrease in viability in these cells versus untreated cells as indicated by the asterisk.