Transcriptomics of Haemophilus (Glässerella) parasuis serovar 5 subjected to culture conditions partially mimetic to natural infection for the search of new vaccine antigens

Abstract

BackgroundHaemophilus (Glässerella) parasuis is the etiological agent of Glässer’s disease in pigs. Control of this disorder has been traditionally based on bacterins. The search for alternative vaccines has focused mainly on the study of outer membrane proteins. This study investigates the transcriptome of H. (G.) parasuis serovar 5 subjected to in vitro conditions mimicking to those existing during an infection (high temperature and iron-restriction), with the aim of detecting the overexpression of genes coding proteins exposed on bacterial surface, which could represent good targets as vaccine candidates.ResultsThe transcriptomic approach identified 13 upregulated genes coding surface proteins: TbpA, TbpB, HxuA, HxuB, HxuC, FhuA, FimD, TolC, an autotransporter, a protein with immunoglobulin folding domains, another large protein with a tetratricopeptide repeat and two small proteins that did not contain any known domains. Of these, the first six genes coded proteins being related to iron extraction.ConclusionSix of the proteins have already been tested as vaccine antigens in murine and/or porcine infection models and showed protection against H. (G.) parasuis. However, the remaining seven have not yet been tested and, consequently, they could become useful as putative antigens in the prevention of Glässer’s disease. Anyway, the expression of this seven novel vaccine candidates should be shown in other serovars different from serovar 5.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1647-1) contains supplementary material, which is available to authorized users.

The Transcriptomic and Bioinformatic Characterizations of Iron Acquisition and Heme Utilization in Avibacterium paragallinarum in Response to Iron-Starvation

“…The identification and quantification of differentially expressed genes (DEGs) can be conducted at a transcriptomic level by using RNA sequencing (RNA-seq) technology. This transcriptomic approach has identified 13 upregulated genes encoding for proteins exposed to iron-restriction stress at the bacterial surface of Hemeophilus ( Glässerella ) parasuis ( Alvarez-Estrada et al, 2018 ). In addition, RNA-seq can also be used to characterize sRNAs, including their secondary structure and predicted mRNA targets.…”

Effect of cAMP Receptor Protein Gene on Growth Characteristics and Stress Resistance of Haemophilus parasuis Serovar 5

“…We hypothesize that the crp gene promotes the uptake of iron from the host by regulating the expression of genes involved in iron uptake. Therefore, we measured the expression of tbpA, tbpB, and cirA, each related to iron uptake (Álvarez-Estrada et al, 2018), by real-time PCR. The results indicated that the expression of tbpA, tbpB, and cirA in the crp mutant were significantly reduced compared with the wild type ( Figure 7B).…”

The regulation of bacterial two‐partner secretion systems

“…Expression of the hxuCBA operon is upregulated in iron–heme restricted medium in a Fur‐dependent manner (Harrison et al, 2013; Whitby et al, 2006). In H. parasuis serovar 5, the hxuCBA operon is upregulated in vitro in conditions mimicking infection with iron limitation and higher temperature (Alvarez‐Estrada et al, 2018). Recently, as mentioned above for the Hmw adhesins and other outer membrane proteins, the expression of the hxuCBA operon was found to be biphasic due to ModA (Atack et al, 2015).…”