The protocols for animal handling were previously approved by our institutional Animal Ethics Committee (protocol number 63/ 2007). Bone marrow-derived macrophages were isolated from 4 to 6 week old C57Bl/6 female mice and grown and differentiated for 7 days in L929 conditioned medium to an approximate concentration of 2,5610 5 cells/well in 6-well plates. On the day of infection the medium was exchanged against MDEM medium with 1% FCS and the cells were infected with 5610 6 cfu per well with the wild type Lm and L.inn strains as well as the recombinant L.inn::vgc strain for 2 h and 8 h. The cells were lysed and their total RNA was isolated.