Additional file 2: Figure S1. of Quantitative proteomic analysis of cell envelope preparations under iron starvation stress in Aeromonas hydrophila

Schematic representation of siderophore-mediated iron uptake systems and the influence of iron depletion on the cell envelope in A. hydrophila, according to quantitative proteomic analysis. (TIF 2163 kb

Additional file 1: Table S1. of Quantitative proteomic analysis of cell envelope preparations under iron starvation stress in Aeromonas hydrophila

Identification and quantification results using dimethyl labeling based quantitative proteomics. (XLSX 834 kb

Subunit Vaccine Targeting Phosphate ABC Transporter ATP-Binding Protein, PstB, Provides Cross-Protection against <i>Streptococcus suis</i> Serotype 2, 7, and 9 in Mice

Streptococcus suis is a significant pathogen in pigs and a newly emerging zoonotic agent in humans. The presence of multiple serotypes and strains with diversified sequence types in pig herds highlights the need for the identification of broadly cross-reactive universal vaccine antigen targets, capable of providing cross-protection against S. suis infection. Subunit vaccines based on the conserved proteins shared between different S. suis serotypes are potential candidates for such a universally protective vaccine. In the present study, phosphate ABC transporter ATP-binding protein PstB (PstB), an immunogenic protein of the S. suis bacterium, was expressed and purified, and then subjected to cross-protection evaluation in mice. The PstB protein showed nearly 100% amino acid similarity across a panel of 31 S. suis isolates representing different serotypes, which were collected from different countries. A recombinant PstB (rPstB) protein (S. suis serotype 2) was recognized by rabbit sera specific to this serotype, and induced high levels of IFN-γ and IL-4 in mice immunized with the recombinant protein. These cytokines are considered important for protection against S. suis infection. Immunization of mice with rPstB resulted in an 87.5% protection against challenge with S. suis serotype 2 and 9 strains, suggesting a high level of cross-protection for S. suis serotypes 2 and 9. A lower protection rate (62.5%) was observed in mice challenged with the S. suis serotype 7 strain. These data demonstrate that PstB is a promising target antigen for development as a component of a universal subunit vaccine against multiple S. suis serotypes