Expression of α-defensins by human eosinophils. Intracellular α-defensin (HNP1-3) expression on eosinophils (eosino) and neutrophils (neutro) was analyzed with RT-PCR (A), flow cytometry (B), and Western blot (C). (D) α-defensin expression on EPO⁺ crystalloid granules purified from human eosinophils. Staining with control isotype antibodies is represented. Results correspond to one representative eosinophil donor. (E) Immunofluorescence and confocal (insets) analysis of human eosinophils with the use of Alexa Fluor 555 goat anti–mouse secondary antibody (red) to detect the HNP1-3 immunoreactivity or Alexa Fluor 488 streptavidin (green) to detect immunoreactivity against MBP or EPO.