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

Abstract

In our previous studies, we have identified several in vivo-induced antigens and evaluated their potential as subunit vaccine candidates in a murine model, in which the recombinant protein GalT showed the most potent immunogenicity and immunoprotective efficacy against Actinobacillus pleuropneumoniae. To exploit a more efficient way of delivering GalT proteins, in this study, we employed the widely studied E. coli outer membrane vesicles (OMVs) as a platform to deliver GalT protein and performed the vaccine trial using the recombinant GalT-OMVs in the murine model. Results revealed that GalT-OMVs could elicit a highly-specific, IgG antibody titer that was comparable with the adjuvant GalT group. Significantly higher lymphocyte proliferation and cytokines secretion levels were observed in the GalT-OMVs group. 87.5% and 50% of mice were protected from a lethal dose challenge using A. pleuropneumoniae in active or passive immunization, respectively. Histopathologic and immunohistochemical analyses showed remarkably reduced pathological changes and infiltration of neutrophils in the lungs of mice immunized with GalT-OMVs after the challenge. Taken together, these findings confirm that OMVs can be used as a platform to deliver GalT protein and enhance its immunogenicity to induce both humoral and cellular immune responses in mice. 2096 Quan et al. J. Microbiol. Biotechnol.

Significant increase in the secretion of extracellular vesicles and antibiotics resistance from methicillin-resistant Staphylococcus aureus induced by ampicillin stress

“…It has been demonstrated in the past that vesicles can defense bacteria by degrading some β-lactam antibiotics, like amoxicillin, ampicillin, cefoperazone, and cefotaxime through their own proteins which are related to β-lactam resistance 7,9,19 . Packed into vesicles, substances related to antibiotic resistance can be delivered over long distances, unharmed by dilution and degradation 14 ; such packaging poses a great benefit for the antibiotic resistance mechanism of the bacteria.…”

“…EVs are defined as spherical, and bilayered proteolipids which form lumen-containing spheres with an average diameter of 20-200 nm, and composed of proteins from various cellular origins, unique lipids, enzymes, toxins and nucleic acids 7,8,12,13 . Packed within vesicles, the cargo molecules can be transported over long distances away from dilution and degradation, which might explain the effective interaction among bacteria 14 . These vesicles have been elucidated to play diverse roles [7][8][9]12,15 , thus EVs are considered the powerful intercellular and interspecies 'communicasomes' in the microbial ecosystem.…”

Identification of the immunodominant neutralizing regions in the spike glycoprotein of porcine deltacoronavirus

“…Mouse and rabbit serum titers were assessed by ELISA as previously described with some modifications (Quan et al, 2018). Briefly, 96-well ELISA plates were pre-coated with 1 ug/well of purified PDCoV overnight at 4°C.…”

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

“…Lymphocyte proliferation assays were performed as previously described with some modifications [44]. Two weeks after booster immunizations of rPotD plus MONTANIDE™ GEL 01 adjuvant, primary spleen lymphocytes from mice in both the mock and immunized groups were separated and maintained for 72 h at 37 • C with 5% CO 2 .…”