To examine the effect of pyruvate dehydrogenase kinase (PDK) inhibition on immune polarity, we used flow cytometry to analyze isolated splenocytes for CD4⁺ T cells and CD11c⁺ DCs obtained from post–cecal ligation and puncture (CLP) mice with or vehicle (CLP⁺ vehicle) vs. DCA (CLP⁺ DCA) treatment. Isolated splenocytes were assayed 6 hours after DCA/vehicle treatments and compared with SHAM control. The proportion of total CD4⁺ cells among total splenocytes was significantly lower in both the sepsis groups (CLP⁺ vehicle and CLP⁺ DCA) and was unaffected by DCA (A). The proportion of CD25⁺FoxP3⁺CD4⁺ Tregs were not significantly higher in CLP⁺ vehicle group vs. SHAM, while the proportion of CD25⁺FoxP3⁺CD4⁺ cells in the CLP⁺ DCA group was significantly lower vs. CLP⁺ vehicle group (B). Sepsis also induced an increase in the frequency of CD11c⁺ cells in CLP⁺ vehicle vs. SHAM group, and this trend was not affected by DCA (C). However, sepsis caused a marked fall in IL-12⁺CD11c⁺ cell frequency in CLP⁺ vehicle vs. SHAM group and a significant increase in IL-12⁺CD11c⁺ cells vs. CLP⁺ vehicle group (D). A, SHAM n = 9, CLP n = 14, CLP⁺ DCA n = 13; B, SHAM n = 5, CLP n = 5, CLP⁺ DCA n = 3; C, SHAM n = 2, CLP n = 4, CLP⁺ DCA n = 5; D, SHAM n = 2, CLP n = 4, CLP⁺ DCA n = 5. Assessed by 1-way ANOVA with Sidak’s post hoc multiple comparisons. *P < 0.05.