During the periods of experimental pulmonary tuberculosis, there are high concentrations of ACh and expression of choline acetyltransferase (ChAT) in lung epithelial cells and macrophages at the early infection stage, besides, the upregulation of lung ACh was even higher and coincided with ChAT and α7nAChR subunit expression in immune cells at late progressive TB [135]. Here, CHAT is linked to tuberculosis.