SEROLOGICAL PROTEOME ANALYSIS OF F. TULARENSIS

The intracellular pathogen, Francisella tularensis, represents the etiological agent of tularemia, a severe respiratory disease of humans and animals. F. tularensis is considered a potential bio-threat agent and accordingly, is included in the CDC list of A-category select agents.

With the objective of identifying immuno-dominant bacterial antigens expressed upon exposure of experimental animals to F. tularensis, we conducted a serological-proteome analysis (SERPA) which included: (a) 2-DE separation of protein-extracts prepared from in vitro-cultured stationary F. tularensis cells, (b) MS-MS assisted identification of abundant proteins and (c) 2-DE Western-blot probing of proteins with a repertoire of sera collected from mice or rabbits immunized with F. tularensis of the Live Vaccine Strain (LVS) or virulent Schu4 strain. These experimental animals were immunized by a variety of live, attenuated or inactivated bacterial cultures, by different routes of administration, enabling identification of about 30 bacterial antigens; several of these were not previously documented as immunogens. The kinetics of the sero-convertion process of the infected animals was determined with respect to several major antigens. These novel identified immunogens have potential significance in the pathogenesis of F. tularensis as well as possible relevance for the development novel diagnostic, disease progression biomarkers and therapeutic strategies.