Identification of candidate antigen in Whipple's disease using a serological proteomic approach.

Whipple's disease (WD) is a chronic multisystemic infection, caused by Tropheryma whipplei, a Gram-positive rod. Recently, a reliable method has been developed for cultivating T. whipplei in vitro. This together with the availability of complete genome sequence of T. whipplei prompted us to initiate proteome analysis of T. whipplei. The objective of the present study was to identify candidate proteins for serological diagnosis of WD. Immunoreactivities of sera collected from 18 patients with WD were compared with those of 24 control subjects who did not have WD. For this, we used 2-DE, immunoblotting, and MS. In total, we identified 23 candidate antigenic proteins. These included a subset of six proteins, each of which was found significantly more frequently in cases as compared to their controls. The remaining 17 proteins were found exclusively in cases. The methods we used in the current study enabled us to identify candidate antigens that, in our view, might be useful for serological diagnosis of WD.