Putative virulence factors of Corynebacterium pseudotuberculosis FRC41: vaccine potential and protein expression

Abstract

BackgroundCorynebacterium pseudotuberculosis, a facultative intracellular bacterial pathogen, is the etiological agent of caseous lymphadenitis (CLA), an infectious disease that affects sheep and goats and it is responsible for significant economic losses. The disease is characterized mainly by bacteria-induced caseous necrosis in lymphatic glands. New vaccines are needed for reliable control and management of CLA. Thus, the putative virulence factors SpaC, SodC, NanH, and PknG from C. pseudotuberculosis FRC41 may represent new target proteins for vaccine development and pathogenicity studies.ResultsSpaC, PknG and NanH presented better vaccine potential than SodC after in silico analyses. A total of 136 B and T cell epitopes were predicted from the four putative virulence factors. A cluster analysis was performed to evaluate the redundancy degree among the sequences of the predicted epitopes; 57 clusters were formed, most of them (34) were single clusters. Two clusters from PknG and one from SpaC grouped epitopes for B and T-cell (MHC I and II). These epitopes can thus potentially stimulate a complete immune response (humoral and cellular) against C. pseudotuberculosis. Several other clusters, including two from NanH, grouped B-cell epitopes with either MHC I or II epitopes. The four target proteins were expressed in Escherichia coli. A purification protocol was developed for PknG expression.ConclusionsIn silico analyses show that the putative virulence factors SpaC, PknG and NanH present good potential for CLA vaccine development. Target proteins were successfully expressed in E. coli. A protocol for PknG purification is described.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0479-6) contains supplementary material, which is available to authorized users.

A panel of recombinant proteins for the serodiagnosis of caseous lymphadenitis in goats and sheep

“…Currently available diagnostic tools provide limited efficacy. Recent analysis of the C. pseudotuberculosis pangenome allowed the discovery of new bacterial proteins presenting B‐cell epitopes (Santana‐Jorge et al ., ), and another study provided new insights in the use of the CP40 protein as an immunogenic through bioinformatics analysis (Droppa‐Almeida et al ., ). By employing some of these newly discovered antigens in the development of immunoenzymatic assays, the present work demonstrated that several of these molecules are broadly recognized by the host immune system and thus can be used to support accurate immunodiagnostic assays.…”

“…Conversely, Santana‐Jorge et al . () previously described that this protein has a significant number of B‐cell epitopes. The present in vivo result, which differed from the predictions of the bioinformatics analysis, may result from low expression of the antigen in clinical isolates of the bacteria, or because most bioinformatics software packages base their analyses on murine and human immunological data.…”

“…Sequencing and subsequent analyses of the genomes of more than 70 strains of C. pseudotuberculosis have provided information regarding the molecular and genetic basis of bacterial virulence and led to the discovery of new and promising antigens Brum et al, 2017). In particular, the FRC41 strain genome contains a gene that codes for protein kinase G (PknG) (Trost et al, 2010), although its specific role remains to be determined (Santana-Jorge et al, 2016). This molecule attracted specific interest because a homologous protein from Mycobacterium tuberculosis blocks fusion between the host macrophage phagosome and the lysosome during phagocytosis (Walburger et al, 2004;Warner and Mizrahi, 2007).…”

“…This molecule attracted specific interest because a homologous protein from Mycobacterium tuberculosis blocks fusion between the host macrophage phagosome and the lysosome during phagocytosis (Walburger et al, 2004;Warner and Mizrahi, 2007). Notably, it had already been revealed that PknG presents significant B-cell epitopes (Santana-Jorge et al, 2016). Corynebacterium pseudotuberculosis is also able to produce a low molecular weight oxidoreductase called glutaredoxin (Lillig and Berndt, 2013), which participates in several cellular functions, such as signal transduction and the defence against oxidative stress (Prinz et al, 1997).…”

rSodC is a potential antigen to diagnose Corynebacterium pseudotuberculosis by enzyme-linked immunoassay

“…The complete sequencing of the C. pseudotuberculosis genome, combined with the introduction of more advanced technologies, such as mass spectrometry, brought new perspectives to the study of proteins excreted by microorganisms as potential therapeutic, vaccine, or immunoassay targets (D'Afonseca et al 2010;Bastos et al 2012;Araújo et al 2019). Some of the highlighted immunoassay and vaccine development target proteins include diptheric toxin repressor homologue (DTxR), Trx and TrxR thioredoxin complex proteins, LexA proteins, superoxide dismutase-C (SodC), SpaC, neuraminidase H (NanH), and PknG serine/threonine kinases (Trost et al 2010;Hall et al 2011;Lin et al 2016;Santana-Jorge et al 2016).…”