Fig. 4.

The engineered receptor Di is sufficient to mediate both chemotaxis and transendothelial migration in immune cells. (A) Transendothelial migration is a critical step in the overall process of cellular homing that also includes adhesion to endothelium and chemotaxis. (B) HL-60 neutrophils and primary human T lymphocytes stably expressing Di were tested for their ability to transmigrate through a tight endothelial monolayer grown on a porous fibronectin-coated transwell membrane in response to both a CNO gradient as well as a positive control chemoattractant (100 nM fMLP and 50 ng/mL SDF-1a, respectively). Both cell types exhibited migration in the presence of CNO. Mean ± SEM for n = 3 (HL-60) or n = 4 (T lymphocytes) replicates is shown (**P < 1e−4, *P = 0.02 by Student t test).