Being a facultative intracellular bacterium makes Lm particularly attractive as a potential live vaccine vector for the induction of cell-mediated immunity to foreign antigens [7, 8] . However, despite its capability to induce effective CD8 + T-cell responses the safety of recombinant Lm remains an important issue, as infections with Lm can cause severe and life-threatening infections [9] . Moreover, infection with Lm is mainly accompanied by undesired CD4 + T-cell mediated delayed type hypersensitivity (DTH) responses and granulomatous inflammation [10, 11] . Therefore the use of Lm in a clinical setting is associated with major risks limiting its potential as an effective vaccine vector.