Identification of immunodominant Bartonella bacilliformis proteins: a combined in-silico and serology approach
Alexander A. Dichter, Tilman Schultze, Anne Wenigmann, Wibke Ballhorn, Andreas Latz, Elif Schlüfter, Palmira Ventosilla, Humberto Guerra Allison, César Ugarte‐Gil, Pablo Tsukayama, Volkhard A. J. Kempf
Abstract
BACKGROUND: Bartonella bacilliformis is the aetiological agent of Carrión's disease, a biphasic and highly lethal illness formerly restricted to the South American Andes that is now spreading to adjacent areas. Reliable serodiagnostic approaches and vaccines are urgently needed. In this study, we aimed to identify immunodominant proteins of B bacilliformis and to establish novel and reliable serodiagnostic tools. METHODS: We used a reverse vaccinology approach in combination with an analysis of heterologous genomic expression libraries to identify immunodominant proteins, on the basis of the genome sequences of B bacilliformis strains KC583 and KC584. Antigens were screened with serum samples collected from Peruvian patients with B bacilliformis infections and from German healthy blood donors without history of travel to South America. We further analysed immunoreactive proteins of B bacilliformis with immunoblotting and line blots. We used selected target proteins to develop a diagnostic ELISA. To assess the performance of this ELISA, we did receiver operating characteristic analyses to assess the area under the curve, cutoff values, sensitivities, and specificities with 95% CIs. FINDINGS: cutoff of 0·34, sensitivity was 76·9% (56·4-91·0) and specificity was 93·8% (86·9-97·7) for all Peruvian patient samples. INTERPRETATION: This novel ELISA could represent a useful serodiagnostic tool for future epidemiological studies of B bacilliformis in endemic areas. Additionally, the immunodominant antigens we have identified could provide a first basis for future vaccine development to prevent the highly lethal Carrión's disease. FUNDING: DRUID (Novel Drug Targets against Poverty-Related and Neglected Tropical Infectious Diseases) Initiative and Robert Koch Institute. TRANSLATIONS: For the Spanish and Quechua translations of the abstract see Supplementary Materials section.