Fig 4.

Shedding of TNFR1 during S. aureus infection. Groups of mice were inoculated intraperitoneally with wild-type S. aureus (light shaded boxes), a protein A-deficient mutant (spa-deficient mutant) (dark shaded boxes), or PBS (control) (open boxes). At different time points, sTNFR1 (A) and TNF-α (B) levels in serum were quantified by ELISA. Each box represents an individual group of mice, and horizontal lines show the median value for each group. Asterisks indicate significant differences (*, P < 0.05; **, P < 0.01; ***, P < 0.001) by the Mann-Whitney test for nonparametric data. (A) The change in sTNFR1 levels (ΔsTNFR1) was calculated for each individual mouse at the indicated time points as the sTNFR1 level after inoculation minus the sTNFR1 level prior to inoculation. (B) The change in TNF-α levels (ΔTNF-α) was calculated for each individual mouse at the indicated time points as the TNF-α level after inoculation minus the TNF-α level prior to inoculation. Basal levels of sTNFR1 and TNF-α prior to inoculation (median values) were 1,500 pg/ml and 45 pg/ml, respectively.