TLR2 and mucositis: Yang et al. (2021) found that L. plantarum may inhibit the activation of the p38 and ERK1/2 MAPK signaling pathways mediated by TLR-4 to combat the excessive activation of the innate immune response caused by ETEC K88. Lactobacillus delbrueckii CIDCA 133 improves 5-fluorouracil chemotherapy-induced mucositis by regulating inflammatory pathways through the TLR2/4/Myd88/NF-κB signaling pathway (Barroso et al., 2022). Bacillus enhances intestinal immune function and is associated with the TLR2/4/Myd88/NF-κB signaling pathway (Du et al., 2018).