IL6 and infection: We next sought to examine the effect of prophylaxis on the host inflammatory response, using cytokine/chemokine biomarkers in which elevated levels are associated with infection severity and/or disease progression, such as IL-6,27–30 TNFα28,31,32 and MIP-1α.33,34 As expected, elevation of plasma IL-6 (uninfected <1.5 pg/mL) and TNFα (uninfected 2.5 ± 0.4 pg/mL) observed in vehicle control animals were significantly dampened in CTC-177- or colistin-treated mice (P < 0.0001) (Figure 3e, Table S2).