hIL4I1 down-regulates TCRζ chain levels on T lymphocytes. (A) T lymphocytes were incubated through transwells without beads (T = O, dashed line), with empty beads (black area), with mock beads (gray area), or with hIL4I1-HEK–covered beads (white area) and TCRζ chain expression at the indicated times was evaluated by flow cytometry in permeabilized cells using a monoclonal antibody. Data are expressed as mean fluorescence intensity (MFI). MFIs for each time point are shown in the upper left corner (empty beads/mock beads/hIL41I beads). (B) Inhibition of TCRζ chain expression by hIL4I1 is expressed as average TCRζ percentage expression in the presence of hIL41I compared with T cells incubated with mock beads. *P = .01; **P = .006.