Identification of a Francisella tularensis LVS outer membrane protein that confers adherence to A549 human lung cells.

Francisella tularensis is a highly pathogenic bacterium; however, little is known about its initial interactions with mucosal surfaces of the human respiratory tract. To investigate these interactions, we tested whether two Francisella strains could adhere to A549 human lung epithelial cells. We found that LVS adhered well to these cells while Francisella novicida adhered poorly. We used surface biotinylation to identify bacterial proteins that might mediate this adherence. We report the identification of the F. tularensis surface protein FsaP, which, when expressed in nonadherent Escherichia coli, confers recombinant bacteria with the ability to bind to A549 cells.