CD40L (human) (multimeric) (rec.) does not need an enhancer to induce B cells activation. Method: PBL cells were incubated in 96-well plates (2x10^5 cells/well in 100 ul RPMI supplemented with 10% FCS) for 24 hours at 37 degrees C with the indicated concentration of CD40L (human) (multimeric) (rec.) or CD40L (h) in the presence and absence of 1 ug/ml Enhancer (Prod. No AG-35B-0001). Cells were washed with PBS and stained with 2 ul each CD86-PE and CD19-FITC in 50 ul FACS buffer (PBS, 5% fetal calf serum, 0.02% azide) for 20 minutes. at 4 degrees C in the dark. After two washes in FACS buffer, samples were then analyzed by flow cytometry.