- Select Listeria monocytogenes subtypes commonly found in foods carry distinct nonsense mutations in inlA, leading to expression of truncated and secreted internalin A, and are associated with a reduced invasion phenotype for human intestinal epithelial cells. Nightingale, K.K., Windham, K., Martin, K.E., Yeung, M., Wiedmann, M. Appl. Environ. Microbiol. (2005)