Figure 4.
OX40/OX40L interaction increases NK cell cytotoxicity in response to ALL cells.
(A and B) OX40L-positive polyclonal NK cells were cultured for 2 hours with OX40-negative JURKAT (left) or OX40-positive SD-1 ALL cells (right) in the absence or presence of blocking OX40 F(ab')2 or isotype control (2 μg/ml each). NK cell reactivity was evaluated by time-resolved fluorometric assays. (A) Exemplary results representing means of triplicates are shown. (B) Combined data of five independent experiments for each ALL cell line at an E:T ratio of 10:1 (control: white bars, OX40 blockade: black bars). Mean values and SD are depicted.
*Statistically significant differences, P<.05.