Total distance traveled (A) and total time spent in the center field (B) of a square enclosed arena for BALB/c and Rag2−/− mice 24 hours after receiving an LPS dose of 1 mg/kg of body weight. Immobility time (C) in the forced swim test 26 hours after LPS administration. (D) Time-course of plasma corticosterone concentrations. Analysis by two-way ANOVA revealed significant differences: (A) Distance traveled, main effects of LPS (p < 0.0001) and genotype (p = 0.0001), interaction (p = 0.0499). (B) Time in center, main effects of LPS (p = 0.0001) and genotype (p = 0.0255). (C) Immobility time: main effect of LPS (p = 0.0147). (D) Plasma corticosterone: main effects of time (p < 0.0001) with an interaction between time and genotype (p = 0.034). Newman-Keuls or Fisher’s LSD post hoc test: * p < 0.05, *** p < 0.001, **** p < 0.0001. See text for planned comparisons differences.