[Immunologic foundations of new vaccination strategies]

Vaccines provide cost-efficient means for control of infectious diseases. Yet, several infectious diseases exist, for which efficacious vaccines are not available, as yet. Recent progress in immunology has led to the identification of the parameters which promote the development of the most appropriate immune response that develops against a given infectious agent. Major criteria are the conditions of intracellular antigen processing which regulate activation of CD4 or CD8 T-cells. CD4 T-cells play a major role in the control of intracellular bacteria, protozoa and fungi, and CD8 T-cells are of importance for combat of viruses and certain intracellular microbes that evade from the phagosome into the cytoplasm. Equally important are the conditions which dictate the development of T-cell populations secreting distinct cytokine patterns of Th1 or Th2 type with Th1 cells being responsible for combat of intracellular bacteria and Th2 cells playing a major role in the control of helminth infections. Understanding how the host regulates the development of the most appropriate defence mechanisms together with modern insights into molecular genetics for manipulation of microbial agents will promote the development of a novel generation of vaccines. Such vaccines will not only contribute to control of infectious agents, but also allow novel strategies towards therapy of tumors, autoimmune disease and allergy.