Electron microscopy of spleen from a

Fth^+/− mouse. (A) At this low magnification, several spleen cells are visible, such as macrophage (M), lymphocyte (L), neutrophil (N), and erythrocyte (E). Arrows indicate electron-dense intracytoplasmic vesicles likely to contain iron (× 4000). (B) Higher magnification of 2 macrophage intracytoplasmic vesicles, showing typical paracrystalline arrangements of iron deposits (no counterstaining, × 20 000).