In-silico identification of linear B-cell epitopes in specific proteins of Bartonella bacilliformis for the serological diagnosis of Carrion's disease

Abstract

Carrion´s disease is caused by Bartonella bacilliformis, it is a Gram-negative pleomorphic bacterium. B. bacilliformis is transmitted by Lutzomyia verrucarum in endemic areas of the Peruvian Inter-Andean valleys. Additionally, the pathogenicity of B. bacilliformis involves an initial infection of erythrocytes and the further infection of endothelial cells, which mainly affects children and expectant women from extreme poverty rural areas. Therefore, the implementation of serological diagnostic methods and the development of candidate vaccines for the control of CD could be facilitated by the prediction of linear b-cell epitopes in specific proteins of B. bacilliformis by bioinformatics analysis. In this study, We used an in-silico analysis employing six web servers for the identification of epitopes in proteins of B. bacilliformis. The selection of B. bacilliformis-specific proteins and their analysis to identify epitopes allowed the selection of seven protein candidates that are expected to have high antigenic activity.

Fig 1. Workflow of in-silico analysis for selection of specific protein candidates.

A) Screening workflow for selection of non-homologous proteins; B) Percentage identity of the 131 non-homologous proteins.

Fig 2. Schematic representation of linear B-cell predictions of the top seven proteins with more linear B-cell epitopes, generated with R library ggplot2.

Fig 3

3D representation of the seven most promising proteins and their B-cell linear epitopes: A) Prot 81; B) Prot 288; C) Prot 447; D) Prot 492; E) Prot 504; F) Prot 612; G) Prot 689. The prediction was done by Phyre 2 and Protein models are displayed by using the software chimera. Colored regions represent epitopes predicted by at least three bioinformatics tool servers.