Figure 4
Complement C3 ablation reduces interleukin (IL)-1β expression in infiltrating neutrophils. (a) Colitis-associated cancer (CAC) was induced in C3−/− mice and wild-type (WT) littermates according to the regimen as described in the Methods. On day 60, after initiating CAC induction, colon explants were cultured ex vivo for 24 h. IL-1β contents in the supernatants were determined by enzyme-linked immunosorbant assay (ELISA). (b) Neutrophils (Gr-1hiCD11b+) in lamina propria were isolated and IL-1β expression was examined by real-time reverse-transcriptase–PCR (RT-PCR). (c) Neutrophil infiltration in tumor tissues was detected by staining with anti-Gr-1 antibody. Scale bar=500 μm (upper) and 100 μm (lower). Right: summarized results. (d) C3−/− mice were injected intraperitoneally with recombinant mouse IL-1β (rIL-1β; 1 μg per mouse) or phosphate-buffered saline (PBS) every other day during CAC induction. On day 60, colons were dissected and tumor number was counted. Each group consists of 6 to 10 mice. *P<0.05; **P<0.01; ***P<0.001 vs. WT littermates. HPF, high-power field.
