The protective antigens of Rickettsia spp. remain unidentified and previous vaccines have only provided moderate protective immunity; the development of a modern safe and effective vaccine is a priority. Currently, I am involved in the characterization of the correlates of immunity in rickettsial infections as well as in the identification of relevant cross-protective rickettsial antigens recognized by T lymphocytes for vaccine development. I consider that the study of host-pathogen/molecule/cell interactions is crucial to understand the underlying mechanisms associated to the immuno-pathobiology of infectious diseases. My long term goal is to contribute to the design of immunotherapeutic agents for prevention, treatment and modulation of human infectious diseases.