Fig. 5. Correlation of HP1 redistribution with lymphocyte activation. (A) Co-staining of non-treated (NT) and stimulated (PHA, LPS) PBLs with anti-HP1 (green) and anti-Ki-67 (red) antibodies. Note that cells with coarse HP1 foci are scarce in the control but increase substantially after treatment. As expected, the number of the intensely stained figures is rather small in the LPS sample since B cells constitute a very small percentage (25-28%) of total blood lymphocytes. Bar, 15 µm. (B) Staining of non-treated and stimulated PBLs with anti-HP1 (green) antibodies and BrdU (red). The induced cells have entered the cell cycle and incorporated BrdU. Bar, 15 µm. (C) HUT-78 monocultures and LiCl-treated cells stained with the indicated antibodies. Asterisks denote mitotic cells. Notice that addition of LiCl affects only the rate of cell division and not the distribution pattern of HP1. Bars, 10 µm and 5 µm as indicated. (D) Graphic representation of the mitotic index of HUT-78 cells prior to and after incubation with LiCl. 1,000 cells were analyzed in each case.