Overexpression of the intracellular domain of FcαRI by cell permeable tat-peptides inhibits the binding of IgA beads to Ba/F3 cells and human eosinophils.

Overexpression of the intracellular domain was also obtained with tat-peptides (A). Both cytokine-starved Ba/F3_FcαRI cells (B) and purified human eosinophils (C) were incubated with 100 μM of the tat-FcαRI (wt), tat_S>A or a nonrelevant scrambled peptide (tat-SCR). After stimulation for 15 minutes of the Ba/F3 cells with IL-3 (1:1000) and the eosinophils with IL-5 (10⁻⁹M), rosette assays were performed, and binding of IgA beads was counted. Results are expressed as rosette index (number of beads/100 cells) and as means ± SE (n = 3).