Main content area

Lactic acid bacteria secrete toll like receptor 2 stimulating and macrophage immunomodulating bioactive factors

Ren, Chengcheng, Cheng, Lianghui, Sun, Yue, Zhang, Qiuxiang, de Haan, Bart J., Zhang, Hao, Faas, Marijke M., de Vos, Paul
Journal of functional foods 2020 v.66 pp. 103783
Toll-like receptor 2, health effects assessments, health promotion, humans, immunomodulation, interleukin-10, lactic acid bacteria, ligands, macrophages, tumor necrosis factor-alpha
Lactic acid bacteria (LAB) can support host health and crosstalks between ligands on bacterial cells and Toll-like receptors (TLR) are known as key inducers of these health effects. LAB-secreted bioactive factors also possess health-promoting properties but the underlying mechanisms remain to be identified. Here, we report that secreted factors of different LAB strains induce cytokine (IL-10 and TNF-α) production by THP1-differentiated human macrophages in a species- and strain-dependent manner. LAB-secreted products also drive immune-stimulating and anti-pathogenic M1-macrophage polarization. Moreover, bacterial supernatants induce species- and strain-dependent TLR2 activation. Several bacterial strains such as L. casei CCFM9 and L. brevis CCFM498 cannot activate TLR signaling, but their secreted products strongly activate TLR2. This indicates that LAB-secreted components may further boost the functional effects of bacterial strains. Our results confirm direct interactions of LAB-secreted components with TLRs, and provide novel insights in how LABs may provide immune-modulation.