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. 2022 Apr 14;13:789366. doi: 10.3389/fimmu.2022.789366

Figure 2.

Figure 2

Low pH reduces NO production and impairs anti-leishmanial defenses of LPS/IFN-γ-coactivated macrophages. (A, B) BMDM were stimulated with LPS (10 ng/mL)/IFN-γ (20 ng/mL) or left unstimulated (ns) for 24 - 72 h. Where indicated, 10 mM lactic acid (LA) or 10 mM sodium lactate (NaL) were added. (A) Nitrite levels were determined at indicated time points (means + SEM, n = 10-29 samples from at least four independent experiments; *p < 0.01, Student’s t-test + Welch correction or Mann-Whitney test). (B) Nitrite levels were determined at indicated time points (mean + SEM, n = 16-40 samples from ten independent experiments; *p <0.01, Mann-Whitney test). (C) As in (A), but cells were stimulated with 10 mM HCl for 24 h (means + SEM; n = 12-16 from at least two independent experiments; *p < 0.05, Student’s t-test or Mann-Whitney test). (D–G) BMDM were infected with L. major and costimulated with LPS (20ng/mL)/IFN-γ (20 ng/mL) or left unstimulated (ns) for 72 h. Where indicated cells were additionally exposed to 10 mM HCl or 10 mM LA and/or 25 µM DETA-NO (DETA). (D) Infection rate (mean + SEM, n = 29-30 high power fields from three independent experiments; *p < 0.05, Kruskal-Wallis test and Dunn post hoc test). (E) Infection rate (mean + SEM, n = 16 high power fields from two independent experiments; *p < 0.05, ANOVA with Bonferroni’s test). (F) Nitrite content of supernatants (mean + SEM, n = 14 from three independent experiments; *p < 0.05, Kruskal-Wallis test and Dunn post hoc test. (G) Infection rate (mean + SEM, n = 18 high power fields from three independent experiments; *p < 0.05, Kruskal-Wallis test and Dunn post hoc test).