Figure 4
Interleukin-6 (IL-6) secretion by lamina propria (LP) mononuclear phagocytes in colitis-associated cancer (CAC)–bearing mice is regulated by neutrophil-derived IL-1β. (a) Dendritic cells (DCs; CD11c+CD11b+) and macrophages (F4/80+CD11b+) in the colon LP of mice treated with IL-1R antagonist (IL-1Ra) or vehicle during CAC induction were sorted by fluorescence-activated cell sorting (FACS) respectively and IL-6 mRNA levels were determined by quantitative reverse-transcriptase–polymerase chain reaction (RT–PCR). Six pairs of mice were analyzed. (b, c) Mononuclear phagocytes sorted from the colon LP of CAC-bearing or naive littermates were stimulated with IL-1β (1 μg ml−1) for 48 h and then IL-6 expression was measured by (b) quantitative RT–PCR or (c) enzyme-linked immunosorbent assay (ELISA). The data are pooled from three independent experiments. US, unstimulated. (d) Mononuclear phagocytes were sorted from the colon LP of naive mice and cocultured with neutrophils from naive mice or neutrophils from the lesions of CAC-bearing mice for 48 h with and without IL-1Ra (1 μg ml−1) and then IL-6 levels in the supernatants were measured by ELISA. The data are pooled from two independent experiments. **P<0.01; ***P<0.001.
