OVA-FITC⁺ cells in lymphoid organs are mainly neutrophils. OVA/CFA-immunized mice were injected in the footpad with OVA-FITC, and 6 hours later lymphoid organs were obtained. (A) Density plot graphs show Gr-1 expression versus green fluorescence. (B) Gr-1^high OVA-FITC⁺ cells show high levels of Ly-6G. (C) May-Grünwald-Giemsa–stained cytospin preparations of LNs from OVA-FITC, or PBS-injected, OVA/CFA-immunized mice. Arrows indicate NEs. (D) LNs from OVA/CFA-immunized mice injected with OVA-FITC: (i-ii) (original magnification, ×600) typical polylobed nucleus of OVA-FITC⁺ NEs in cytospin preparation stained with DAPI alone (in blue) (i) or DAPI plus anti–Gr-1–labeled with Alexa Fluor 546 (red) (ii); (iii-iv) (original magnification, ×400) confocal microscopy: OVA-FITC⁺ cells (green) and Gr-1⁺ cells (red) as well as a merged image are shown. Panels C and Di-ii were obtained with conventional microscopy. One typical experiment of 4 performed is shown (n = 3-4 mice per group).