Figure 1.

CD11b⁺Gr1⁺ cells expand in the liver of mice harboring intra-abdominal tumor. (A) C57BL/6 mice were seeded with MCA38 i.p. Liver NPC were then harvested on Day 21 and analyzed for CD11b and Gr1 expression by flow cytometry. Data are representative of experiments done more than five times using at least three mice in each experiment. (B) s.c. MCA38 administration resulted in minimal expansion of intra-hepatic myeloid cells by Day 14. Data are representative of experiments done twice using three mice each time. IP, i.p. (C) Immunoflourescent microscopic analysis of the liver in mice-bearing MCA38 tumor (Day 14) using antibodies against Gr-1 and CD11b. (D) Time course of CD11b⁺Gr1⁺ cellular expansion in multiple compartments of tumor-bearing hosts. Cells were harvested at various time intervals after i.p. MCA38 challenge and analyzed for CD11b and Gr1 coexpression by flow cytometry. CD11b⁺Gr1⁺ cells underwent the highest relative increase in the liver (P<0.05). Averages of two to three mice/time-point are shown. This experiment was repeated three times with consistent results. (E) To determine the turnover of CD11b⁺Gr1⁺ cells in various compartments, on Day 14 after tumor challenge, i.p. MCA38-bearing mice received BrdU (100 μg). Thirty-six hours later, CD11b⁺Gr1⁺ were harvested from various compartments and incorporation of BrdU determined by flow cytometry. This experiment was repeated three times using three mice/group.