Vaccination strategies against intracellular microbes

Leishmaniasis, malaria, tuberculosis, leprosy, typhoid and listeriosis are infectious diseases which, together, cause enormous public health problems throughout the world. The etiologic agents of these diseases, Leishmania ssp., Plasmodium ssp., Mycobacterium tuberculosis, Mycobacterium leprae, Salmonella typhi / S. paratyphi or Listeria monocytogenes, respectively, are endowed with the capacity to utilize the intracellular habitat of various host cells, including macrophages, erythrocytes and liver cells. This intracellular habitat effectively protects them from antibody-mediated defence mechanisms, so that T lyrnphocytes are required for acquisition of antimicrobial protection. Protective immunity is best induced by viable vaccines, whereas soluble proteins are generally insufficient. This is not only of great academic interest, but also of ap-