GroEL is an immunodominant surface-exposed antigen of < i > Rickettsia typhi < /i >

by Jessica Rauch, Jessica Barton, Marcel Kwiatkowski, Malte Wunderlich, Pascal Steffen, Kristin Moderzynski, Stefanie Papp, Katharina H öhn, Hella Schw.e, Susanne Witt, Ulricke Richardt, Ute Mehlhoop, Hartmut Schlüter, Verena Pianka, Bernhard Fleischer, Dennis Tappe, Anke Osterloh Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae.Rickettsia (R.)typhi andR.prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) againstR.typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein ofR.typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated byR.typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that t...
Source: PLoS One - Category: Biomedical Science Authors: Source Type: research