Intracellular bacteria as targets and carriers for vaccination

In this review we discuss intracellular bacteria as targets and carriers fo r vaccines. For clarity and ease of comprehension, we focus on three microb es, Mycobacterium tuberculosis, Listeria monocytogenes and Salmonella, with an emphasis on tuberculosis, one of the leading causes of death from infec tious disease. Novel vaccination strategies against these pathogens are cur rently being considered. One approach favors the use of live attenuated vac cines and vaccine carrier strains thereof, either for heterologous antigen presentation or DNA vaccine delivery. This strategy includes both the impro vement of attenuated vaccine strains as well as the 'de novo' generation of attenuated variants of virulent pathogens. An alternative strategy relies on the application of subunit immunizations, either as nucleic acid vaccine s or protein antigens of the pathogen. Finally, we present a short summary of the vaccination strategies against tuberculosis.