FIG. 8.

P72 mice demonstrate an enhanced response to lipopolysaccharide (LPS) challenge. (A) Thymuses were isolated from P72 and R72 mice that were subjected to intraperitoneal injection of 20 mg/kg of LPS or left untreated (UNT); after 4 h, thymuses were harvested, fixed, and stained for p53 phosphorylated on serine 15 using phosphospecific antibody (pSer15). In both P72 and R72 thymuses, approximately 4% of cells stain positively for p53 phosphorylated on serine 15 after 4 h. (B, left) Western analysis of whole-cell lysates from mice treated with 20 mg/kg of lipopolysaccharide (LPS) for 4 h. (Right) Immunoprecipitation-Western analysis of the p65 RelA-p53 interaction in LPS-treated thymocytes. (C) QPCR analysis of control (Hprt1), candidate p53 target genes (Casp4 and Gdf15), and the NF-κB target genes IL-4, Birc3, Tlr2, and IL-6 in thymocytes isolated from mice treated with LPS after 4 h. The results shown are averaged values from 2 independent experiments, each done in duplicate; error bars depict standard errors. (D) Kaplan-Meier plot of the survival of P72 and R72 mice injected with 20 mg/kg of LPS. Statistical significance was calculated using the Wilcoxon 2 sample test.