Figure 3.
In vitro and in vivo effects of S. Typhimurium expressing Ag-e.spike. (a) LDH cytotoxicity assays were performed on cell-free supernatants from Raw 264.7 cells treated with phosphate-buffered saline (PBS) or attenuated unmodified S. Typhimurium, S. Typhimurium carrying the empty expression vector (vec), or S. Typhimurium expressing Ag-spike. The data represent the mean ± standard error of three independent experiments. (b) Bacterial distribution was examined in mice after oral administration 1 × 107 bacterial cells for the indicated time. (c) Survival curves of all mice groups were recorded for up to 8 days. (d) Mice were treated with PBS or 1 × 108 bacteria cells. Serum was collected 7 days after inoculation and interferon-γ (INF-g) levels were analyzed with enzyme-linked immunosorbent assay (ELISA). (* p < 0.05 versus S. Typhimurium (Vec)-treated mice; Student’s t-test).