Characterization and Vaccine Potential of Outer Membrane Vesicles Produced by Haemophilus parasuis

Abstract

Haemophilus parasuis is a Gram-negative bacterium that colonizes the upper respiratory tract of swine and is capable of causing a systemic infection, resulting in high morbidity and mortality. H. parasuis isolates display a wide range of virulence and virulence factors are largely unknown. Commercial bacterins are often used to vaccinate swine against H. parasuis, though strain variability and lack of cross-reactivity can make this an ineffective means of protection. Outer membrane vesicles (OMV) are spherical structures naturally released from the membrane of bacteria and OMV are often enriched in toxins, signaling molecules and other bacterial components. Examination of OMV structures has led to identification of virulence factors in a number of bacteria and they have been successfully used as subunit vaccines. We have isolated OMV from both virulent and avirulent strains of H. parasuis, have examined their protein content and assessed their ability to induce an immune response in the host. Vaccination with purified OMV derived from the virulent H. parasuis Nagasaki strain provided protection against challenge with a lethal dose of the bacteria.

Polyamine Transport Protein PotD Protects Mice against Haemophilus parasuis and Elevates the Secretion of Pro-Inflammatory Cytokines of Macrophage via JNK–MAPK and NF–κB Signal Pathways through TLR4

“…Haemophilus parasuis, or Glaesserella parasuis (G. parasuis) according to the new taxonomic reclassification, is normally a benign swine commensal in upper respiratory tract but may cause severe vascular lesions and multiorgan dysfunction, eliciting serious economic losses annually worldwide [46,47]. Commercial bacterins are often used to vaccinate swine against H. parasuis, but the deficiency in crossreactivity makes sole-serotype inactivated vaccine an ineffective means of protection against this disease [48].…”

Epidemiological and PK/PD cutoff values determination and PK/PD-based dose assessment of gamithromycin against Haemophilus parasuis in piglets

“…There are currently 15 serotypes of H. parasuis and serotypes 1, 5 and 10 are the most virulent causing rapid death of infected piglets [4,5]. The vaccines currently available only provide partial protection due to the serotype diversity and this is problematic because many strains cannot be serotyped [6]. Thus, antibiotic therapy still represents the most effective strategy for controlling the spread of H. parasuis infections.…”

Escherichia coli-derived outer membrane vesicles deliver galactose-1-phosphate uridyltransferase and yield partial protection against Actinobacillus pleuropneumoniae in mice

“…OMVs follow these characteristics. At present, studies have explored the natural OMVs secreted by Haemophilus parasuis, which belongs to the genus Pasteurella, and preliminary investigation explored its potential as a vaccine [37]. Immunization of protein as an antigen alone does not activate T cells, so the presence of costimulatory molecules is required.…”