Gut Microbiota Modulation in Asthma—An In Vitro Study

Objectives: The aim of this work was to investigate whether Bacteroides vulgatus (BV), Clostridium perfringens (CP), Parabacteroides distasonis (PD), and Ruminococcus albus (RA) lysates modulate the secretion of IL-17, INF-γ, IL-2, and TGF-β 1 by human HT-29 cells, PBMCs, and monocytes (MON). Results: CP lysate significantly lowered IL-17 secretion by HT-29 cells vs. control (p < 0.05), but only at a dose of 100 µg. RA lysate reduced IL-17 secretion by HT-29 cells vs. control (p < 0.05), but only at a dose of 400 µg, whereas PD lysate significantly decreased IL-17 secretion by HT-29 cells vs. control (p < 0.05) at both doses. The secretion of IL-17 by PBMCs was significantly reduced after administration of BV and PD lysates (100 µg). BV and PD lysates (400 µg) also significantly decreased IL-17 secretion by MON vs. control (p < 0.05). The secretion of INF-γ by HT-29 cells was significantly lowered vs. control (p < 0.05) after administration of PD and CP lysates (400 µg). CP lysates (100 µg and 400 µg) also significantly reduced INF-γ secretion by MON compared with control (p < 0.05). The secretion of INF-γ by PBMCs was significantly reduced vs. control (p < 0.05) after administration of BV and CP lysates (400 µg). Conclusions: In PBMCs, HT-29 cells, and MON, INF-γ and IL-17 concentrations were significantly lowered by selected bacterial lysates in a dose-dependent manner. However, the low values detected in this experiment may not have an impact on systemic immune status.