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. 2018 Jan 16;14(1):e1006809. doi: 10.1371/journal.ppat.1006809

Fig 5. Myeloid cell expression of STAT3 hamper IL-17 secretion by T cells during M. tuberculosis infection.

Fig 5

The frequency of IL-17-secreting PPD and PMA and ionomycin (P.I) -stimulated CD4+ pulmonary T cells from stat3fl/fl lysm cre and stat3fl/fl mice 4 (A) and 8 (B) weeks after infection with M. tuberculosis was measured by FACS. A representative graph plot from PPD stimulated lungs at 4 w after infection (C) and the mean percentage of IL-17-secreting CD4+ cells ± SEM (A, B) are displayed (n = 6 per group, *p<0.05, **p<0.01 and ***p<0.001 Mann Whitney U test). The mean fold increase of il17a (D), il22 (E), cxcxl5 (F), il23p19 (G) and il6(H) mRNA ± SEM was measured by real time PCR in the total RNA from lungs of stat3fl/fl lysm cre and stat3fl/fl mice at different time points after M. tuberculosis infection (n = 8 per group **p<0.01 Student’s t test). The mean frequency of PPD (I) and PMA and ionomycin (J) -stimulated CD4+ pulmonary T cells from stat3fl/fl lysm cre and stat3fl/fl mice 8 weeks after infection with M. tuberculosis co-secreting or not IFN-γ was measured by FACS (n = 4 per group, *p<0.05, **p<0.01 and ***p<0.001 Mann Whitney U test). A representative graph plot from CD3+CD4+ gated PPD and P.I. stimulated IFN-γ and / or IL-17+ lung cells (K) is depicted. The frequency of both IL-17 and IFN-γ and only IL-17+ secreting cells from stat3fl/fllysm cre is higher as compared to stat3fl/fl controls; the frequency of IL-17+/IFN-γ- is higher than IL-17+/IFN-γ+ cells. This was determined after either PPD or PMA/ ionomycin stimulation (Two-way ANOVA *p<0.05 and *** p<0.0001). Stat3fl/fl lysm cre and stat3fl/fl littermate controls were treated i.p. 1 day before and once per week after aerosol infection with M. tuberculosis with 500 μg anti-IL-17RA M751or left untreated. Mice were sacrificed 4 weeks after the infection and colony forming units (CFU) per lung (L) and spleen (M) were assessed. The CFU per organ of individual mice and the median per group at the indicated time points after infection are depicted. Differences in CFU are significant (*p<0.05, **p<0.01 Mann Whitney U test). The mean fold increase of mpo mRNA ± SEM was measured by real time PCR in lysates from lungs of stat3fl/fl lysm cre and stat3fl/fl mice 4 weeks after infection with M. tuberculosis treated or not with anti-IL-17RA as described above (n≥ 4 per group, *p<0.05 Student’s t test) (N).