Modulation of host immune responses by Bartonella effector proteins

Abstract

Started in May 2011, my first project was collaborated with the group of Prof. Kempf in the Institute of Medical Microbiology and Infection Control at the University Hospital of the Johann Wolfgang Goethe-University in Frankfurt. Two pathogenicity factors of Bartonella henselae have been greater characterized in individual activities: the trimeric autotransporter Bartonella adhesin A (BadA) and the type IV secretion system VirB/D4 (VirB/D4 T4SS). In this study, we deeply investigated how these major virulence factors affect each other in their specific activities. In the second project, I focused on the natural host interface with Bartonella, particularly on the bacterial defense mechanisms against host immunity. To achieve this, my work was divided into two directions. One was to identify which Bartonella effector proteins as immunomodulatory molecules involved in intracellular communications to subvert the immunological signaling cascade. The other was to find the primary niche of Bartonella entry and replication in the natural reservoir host. By understanding the Bartonella infection cycle, I aimed to explore how Bartonella manipulate host immunity towards its pathogenicity in vivo. Taken in vitro and in vivo results together, I sought to complete this project with a comprehensive insight into which Bep displays immunosuppressive properties, how it works and what are the consequences of its function on host immunity.