Skip to main content
. 2010 Jul 6;78(9):3689–3699. doi: 10.1128/IAI.00616-10

FIG. 3.

FIG. 3.

TNF-α pre- and posttreatment alter Shiga toxin 1-mediated lethality. Animals were injected with Stx1, Stx2, rmTNF-α, or saline, as indicated, via the intraperitoneal (i.p.) route. Treatment groups were categorized based on the timing of rmTNF-α injection relative to toxin exposure. (A) Mice pretreated with rmTNF-α prior to Stx1 injection (TNF-α pretreatment group). Mice were injected with 2.0 μg rmTNF-α 24, 6, or 1 h before the administration of 9 μg/kg of Stx1 and monitored for morbidity. The graph represents the results of three independent experiments using a total of 13 mice (n = 13). Three asterisks denotes significance at P < 0.001 compared to Stx1 treatment alone. (B) Mice pretreated with rmTNF-α prior to Stx2 injection (TNF-α pretreatment group). Mice were injected with 2 μg rmTNF-α 24, 6, or 1 h before the administration of 10 ng/kg of Stx2 and monitored for survival. The graph represents results of two independent experiments (n = 10). Two asterisks denotes significance at P < 0.01 compared to Stx2 treatment alone. (C) Mice receiving Stx1 prior to rmTNF-α injection (TNF-α posttreatment group). Mice were given 9 μg/kg of Stx1 and subsequently injected with rmTNF-α 1, 6, and 24 h later and monitored for survival. The graph represents results of two independent experiments (n = 6). The asterisk denotes significance at P < 0.05 compared to Stx1 treatment alone. (D) Neutralizing antibodies were used to protect TNF-α-posttreated animals from increased Stx1 lethality. Briefly, mice were given either 4.0 μg anti-rmTNF-α antibody or 60 ng anti-Stx1 antibody. One hour later, mice were challenged with 4.5 μg/kg of Stx1 followed 1 h later by 2.0 μg rmTNF-α and were monitored for survival during a 7-day period. The graph represents results of two independent experiments (n = 10). An asterisk denotes significance at P < 0.05, and a double asterisk denotes significance at P < 0.01 compared to TNF-α-posttreated animals. All statistical significance was assessed by the log-rank (Mantel-Cox) test using Graphpad Prism version 5 for Mac OS X (Graphpad Software, San Diego, CA).