(A) Surface IgE levels on blood basophils and monocytes following human IgE injection. Before and at 1, 4, 8, and 24 hours after hIgE injection, Tg⁺ and Tg^– mice were bled for flow cytometric analysis of surface IgE levels in basophils and monocytes. Data for Tg⁺ mice are shown in solid lines and for Tg^– mice in dotted lines. Data for 3 mice from one representative experiment of 3 are presented with mean ± SEM. (B–D) Surface IgE levels on blood cDCs (B), lung DCs and monocytes (C), and peritoneal mast cells (D) of Tg⁺ mice following human IgE injection. At each time point following hIgE injection, mice were sacrificed and whole blood, lungs, or peritoneal lavage collected and analyzed by flow cytometry. Data for 9 mice (B), 8 mice (C), or 14 mice (D) from one representative experiment of 2 are presented with mean ± SEM. (E and F) Intracellular localization of human IgE in basophils and monocytes of FCER1A-Tg mice injected with hIgE. At 6 hours after injection, basophils and monocytes were isolated and examined for intracellular human IgE by confocal microscopy as described for Figure 3A. Original magnification, ×60; scale bars: 2.5 μm. (F) Intracellular IgE levels were quantified as in Figure 4B. Thirty images of Tg⁺ monocytes and basophils were analyzed. Resulting values are presented with mean ± SEM. *P < 0.05.