Transmission electron microscopy of immunogold-labeling of RANTES in unstimulated eosinophils. (A) The arrow indicates gold particles associated with electron-dense crystalloid granules, while the arrowhead shows immunogold labeling of extragranular areas. (B) Higher magnification of another cell. (C) Isotype control using mouse IgG1 antibody. Original magnifications: (A), ×9,100; (B), ×34,000; and (C), ×6,900.