Furthermore, in APP/PS1 mice, modification of gut MB is related to increased brain infiltration of Th1 cells (Wang et al., 2019), while ablation of gut MB blocks brain infiltration of Th1 cells and activation of microglia, indicating that gut MB is functional in promoting Th1/microglia inflammatory mechanisms in AD pathogenesis (Wang et al., 2019). The gene discussed is APP; the disease is Alzheimer disease.