are surface proteins found on Listeria monocytogenes
. They exist in two known forms, InlA and InlB. They are used by the bacteria to invade mammalian cells via cadherins
transmembrane proteins. The exact role of these proteins and their invasiveness in vivo is incompletely understood. In cultured cells, InlA is necessary to facilitate Listeria entry into human epithelial cells. While InlB is necessary for Listeria internalisation in several other cell types, including hepatocytes, fibroblasts, and epithelioid cells.