Identification of platelet–eosinophil complexes in lungs taken from allergen-sensitized mice after allergen exposure. Lungs were taken and processed for immunofluorescence examination 30 hours after the start of allergen exposure. Sections were stained for an eosinophil-specific protein (rat anti-MBP; green fluorescence) and for a platelet-specific protein (goat anti-CD41; red fluorescence). (A) Image with filter for only green fluorescence (MBP⁺) (objective lens ×40). (B) Image with filters for both green and red (CD41⁺) fluorescence; tissue eosinophils were observed complexed to platelets (objective lens ×40). (C) Individual platelets can be seen attached to eosinophils. Sections were analyzed using a 100 × objective lens. Sections were analyzed, with immersion oil, using a light fluorescence microscope (AxioSkop 2 Plus; Carl Zeiss, Oberkochen, Germany). Images were analyzed with Lucia Core System 1.0 (Prague, Czech Republic). The Zeiss Achroplan ×100 objective has a numerical aperture (NA) of 1.25 (Figure 3C). Figures 3A and 3B were viewed with a Zeiss Achroplan ×40 objective, and this has an NA of 0.75.