Intracellular localization of CCL3 in HBMEC by immunogold silver staining. (A) In untreated cultures, cytoplasmic staining is faint indicating minimal constitutive expression. Nuclei are counterstained with Giemsa. (B)-(D) The density of the granular black cytoplasmic deposits is increased in cultures treated with (B) TNF-α (100 U/ml)+ IFN-γ (200 U/ml) for 72 hrs, (C) IL-1β (10 U/ml) for 72 hrs and (D) LPS (5 μg/ml) for 48 hrs. (E) Control cultures incubated with secondary antibody only show no staining. Scale bars = 50 μm.