Since TNF-α can stimulate NF-κB activity [54], this implies there is cross talk between NF-κB, TNF-α, and HIF-1α, even under normoxic conditions. Since both mouse strains had pneumonia and we did not measure oxygen saturations, we cannot EPZ015666 order exclude an influence of a hypoxia-induced increase in HIF-1α in the lungs of both strains after infection. However, C57BL/6 mice were clearly afflicted with more extensive lung disease (Figure 1) so this strain might be expected to mount a stronger hypoxic response leading to higher levels of HIF-1α. Since there was more expression see more of HIF1A mRNA in DBA/2

mice at day 14, it appears that the stronger induction of HIF1A in DBA/2 mice may be independent of hypoxia. Hypoxia and inflammation occur

in human patients infected with C. immitis[55, 56] and both those conditions are known to increase levels of the HIF-1α protein [19]. It is quite likely that hypoxia and inflammation act synergistically to increase the level of HIF-1α in this infection, as it has in other models of infection in mice [57]. Cox and Magee [58] noted that spleen cells from DBA/2 mice previously infected with C. immitis and stimulated with formalin-killed spherules produced higher levels of TNF-α than C57BL/6 mice. Furthermore, our previous studies have shown that TNF-α deficient mice cannot be successfully immunized with a live, attenuated vaccine strain of C. immitis[59]. Given the Ivacaftor mouse central role of TNF-α in the inflammatory response it is not surprising that the inhibition of this cytokine is a risk factor for the dissemination of C. immitis in human patients [6]. These observations suggest that TNF-α plays a beneficial role in resistance to coccidioidomycosis, perhaps through activation of NF-κB and HIF-1α. Encouragingly, TNFA, HIF1A and a transcriptional target

of HIF1A (IL6) were all upregulated to a greater extent in DBA/2 compared to C57BL/6 mice at day 14 (Figure 7). This suggests the following Loperamide activation cascade: TNFA → NF-κB → HIF1A → IL6; where NF-κB is primarily regulated at the protein level by degradation of inhibitory IkB proteins and not upregulated at the transcriptional level [60]. However, this result must be interpreted with care since by day 16, TNFA, HIF1A, and IL6 are upregulated in C57BL/6 mice to a greater extent than in DBA/2 mice (Figure 3 and Additional file 1: Figure S3B). Cytokines promoting Th17 development (i.e., TGF-β, IL-6, and IL-1β) and those secreted from Th17 cells (i.e., IL-17a) [61] exhibited a similar pattern of gene expression, i.e., upregulated in DBA/2 at day 14 followed by a receding difference (TGFB, IL1B, and IL17A) or a reversal in differential expression (IL6) at day 16 (Figure 7, Additional file 1: Figure S3, and data not shown). Recently Cole et al.