Figure 1.

Functional comparison between prokaryotic and eukaryotic WT IL-13. Normal human PBMCs were stimulated with increasing concentrations of prokaryotic IL-13 (from Peprotech [P], open circles, or R&D [R], triangles) or eukaryotic IL-13 (COS-7 cell–derived [C], closed circles) for 48 hours. Surface CD23 expression was then assessed by direct immunofluorescence using PE-conjugated anti-CD23 mAb or isotype control, gating on the monocyte population. Two-tailed paired Student’s t test was used to compare responses to different IL-13 preparations. P values are noted for each IL-13 concentration at which a statistically significant difference in the response was detected. The figure shows the mean ± SE of the results obtained from 4 experiments.