Interestingly, treatment with S-1P enhanced the expression of key signaling proteins, including phospho-MAPK (pp38), phospho-Nf-κB, and phospho-STAT3 in the lungs of infected animals during the course of the infection (Figure 10), which may account for S1P–mediated control of pathogenic mycobacteria in infected animals. Here, STAT3 is linked to infection.