Table 1.
TNF-α secretion of F. tularensis-infected J774 cells
| Strain | TNF-α secretion (pg/ml)a |
|
|---|---|---|
| 1 h | 2 h | |
| Noninfected | 156.2 ± 6.3*** | 168.5 ± 10.6*** |
| F. tularensis subsp. holarctica | ||
| LVS | 54.4 ± 3.3 | 40.9 ± 2.8 |
| ΔiglA | 228.1 ± 49.9* | 563.6 ± 14.3*** |
| ΔpdpE | 69.5 ± 5.7 | 37.2 ± 4.1 |
| ΔpdpE/pPdpE+ | 18.9 ± 0.8*** | 27.9 ± 0.9 |
| ΔiglG | 263.9 ± 16.6*** | 240.8 ± 47.4** |
| ΔiglG/pIglG+ | 39.9 ± 0.6*** | 35.0 ± 7.2** |
| ΔiglI | 226.0 ± 37.2** | 381.7 ± 33.9*** |
| ΔiglI/pIglI+ | 67.9 ± 18.7** | 37.5 ± 4.3*** |
| F. tularensis subsp. novicida | ||
| U112 | 225.0 ± 26.6 | 438.1 ± 40.1 |
| ΔiglI::ermC | 266.7 ± 20.0 | 645.9 ± 52.4* |
| ΔiglI::ermC/pIglI+ | 355.0 ± 42.3 | 625.7 ± 40.1 |
F. tularensis-infected (MOI=500) or noninfected J774 cells were incubated in the presence of E. coli-derived LPS (50 ng/ml) for 1 or 2 h. The average TNF-α secretion and standard errors from quadruple samples (n=4) from one out of two representative experiments are shown. In the absence of LPS, the cytokine levels were below the limit of detection for the assay (<15 pg/ml) (data not shown). A Student's 2-sided ttest was used to determine whether the TNF-α secretion induced by the mutants was significantly different from that of the parental strain (Pvalues indicated for each mutant) and whether the TNF-α secretion induced by the complemented strains was statistically different from that induced by their isogenic mutants (P values indicated for each complemented strain).
P < 0.05;
P < 0.01;
P < 0.001.