We investigated the temporal dynamics of C/EBP-β recruitment to the murine SerpinB2 promoter in response to LPS in vivo by chromatin immunoprecipitation (ChIP). RAW 264.7 cells were stimulated with LPS for up to 8 hrs, soluble chromatin was immunoprecipitated with antibodies against DNA binding proteins, and the enriched DNA amplified by both semi-quantitative and qPCR using SerpinB2 proximal promoter specific primers (illustrated in fig. 4A). The results showed that C/EBP-β is constitutively present at the SerpinB2 promoter as demonstrated by its association with the promoter in unstimulated macrophages and increased temporally in response to LPS reaching as much as 10-fold over unstimulated cells after 8 hrs (Fig. 7). Since changes in C/EBP-β phosphorylation states can affect C/EBP-β’s ability to transactivate target genes [38]; [63]; [64], we investigated recruitment to the SerpinB2 proximal promoter of the T217 phosphorylated C/EBP-β isoform (p-C/EBP-βT217), which has been associated with cell survival [65]. p-C/EBP-βT217 was constitutively bound to the SerpinB2 proximal promoter and also present after 1 hr of LPS stimulation (Fig. 7). In contrast to total C/EBP-β, the binding affinity of p-C/EBP-βT217 for the SerpinB2 proximal promoter diminished with LPS stimulation at later timepoints (4 and 8 hrs)(Fig. 7). These data show an inverse relationship between C/EBP-β and p-C/EBP-βT217 recruitment, and indicate that T217-phosphorylated C/EBP-β may not be responsible for increased transcription from the SerpinB2 promoter in response to LPS.