Figure 3.

Cytokine profile in SLΔppGpp- or MG1655-colonized tumors during the suppression stage. (A) Cells were isolated from tumors at 2dpi, and the expression of different cytokines was analyzed by qRT-PCR. HPRT was used as housekeeping gene to assess target gene expression. (B) Tumors were excised and homogenized in protein extraction solution, and the level of cytokines in the supernatant was measured by ELISA. (C) Single cell suspensions derived from tumor tissues were lysed, and total protein was obtained. The expression of caspase-1, pro-IL-1β, IL-1β, IL-18 and IPAF was examined by western blotting. β-actin was used as the loading control. (D) Serum TNF-α levels were measured in an ELISA at the indicated times. Data represent the mean ± SD. *P < 0.05, **P < 0.005, and ***P < 0.001.