(A) Expression of nuclear Ki67 in DC cultures over time. Cytospins were prepared from DC cultures at various times, and stained with either irrelevant control antibody (bottom left) or Ki67 using an indirect immunoperoxidase method as described in Materials and Methods. Ki67 stains the nucleus brown. The percentage of Ki67⁺cells is indicated in each panel. Original magnification × 130. (B) Expression of Ki67 and phenotypic markers in DC cultures. Cytospins were prepared from DC after 7 to 10 days in culture with GM-CSF and IL-4 (e), or GM-CSF/IL-4 and LPS (a through d, f). In each case Ki67 stains the nucleus brown (arrow) and the other MoAb stains red: (a) CD3, (b) CD20, (c) CD40, (d) CD1a, (e) p55, (f) p55. Original magnification × 130.