Fig. 8. Accumulation and proliferation of lymphoma cells in the peripheral lymph nodes following i.v. injection. The indicated fluorescent lymphoma cells were injected i.v. into BALB/c mice. Three-color flow cytometric analysis of their lymph node cell suspensions was performed on days 4, 8 and 12 postinjection to show the accumulation of the different lymphoma cell lines as a function of time. The upper edge of the autofluorescence spot of normal lymph node cells (not shown) was used to determine the horizontal line bordering the lymph node cells (below the line) and the green tumor infiltrating cells (above the line). The percentage of GFP-positive infiltrating tumor cells (above the line; A in each box) in the total lymph node cell suspension (the sum of cells below and above the horizontal line (i.e. 7000 events) was determined by plotting green-fluorescence intensity (on a logarthmic scale) versus forward scatter. The green lymphoma cells (above the horizontal line) were gated and the proportion of BrdU-labeled dividing cells in the S-phase (B in each box) was determined following staining with anti-BrdU antibody and propidium iodide, as indicated in Materials and Methods. The percentage of cells in the S-phase (shown for day 12) was determined by dividing the number of cells framed in G3 by the total cell number (G1+G2+G3) x100. A similar formula was used to calculate the proportion (percentage) of cells in the S-phase at days 4 and 8. Note that the proportion of dividing cells in the population of green cells (i.e. lymphoma cells) is similar in all four cell lines, indicating a similar proliferation rate.
