NOD2 and pneumonia caused by chlamydia: NOD2 recognizes notonly exogen ligands (microbial products) but also endogen ligands (oxidizedLDL-c).92,93 Interactions between NOD2 and bacterial componentsalso take place in the cytoplasm of endothelial cells and cardiomyocytes,illustrated by its response to one of the most frequently detected bacteriain atherosclerotic plaques, Chlamydia pneumonia.