Proteomic analysis of the bacterial pathogen Bartonella henselae and identification of immunogenic proteins for serodiagnosis

Bartonella henselae is a slow growing, fastidious and facultative intracellular pathogen causing cat scratch disease and vasculoproliferative disorders. To date, knowledge about the pathogenicity of this human pathogenic bacterium is limited and, additionally, serodiagnosis still needs further improvement. Here, we investigated the proteome of B. henselae using 2‐D SDS‐PAGE and MALDI‐TOF‐MS. We provide a comprehensive 2‐D proteome reference map of the whole cell lysate of B. henselae with 431 identified protein spots representing 191 different proteins of which 16 were formerly assigned as hypothetical proteins. To unravel immunoreactive antigens, we applied 2‐D SDS‐PAGE and subsequent immunoblotting using 33 sera of patients suffering from B. henselae infections. The analysis revealed 79 immunoreactive proteins of which 71 were identified. Setting a threshold of 20% seroreactivity, 11 proteins turned out to be immunodominant antigens potentially useful for an improved Bartonella‐specific serodiagnosis. Therefore, we provide for the first time (i) a comprehensive 2‐D proteome map of B. henselae for further proteome‐based studies focussed on the pathogenicity of B. henselae and (ii) an integrated view into the humoral immune responses targeted against this newly emerged human pathogenic bacterium.