.  coli outer membrane vesicles (OMVs) - Caspase 11-4/5 inducers

Outer membrane vesicles (OMVs) are small, spherical bodies secreted by Gram-negative bacteria, recently described as potent caspase 11-4/5 inflammasome inducers. They contain various pathogen-associated molecular patterns (PAMPs) such as lipoproteins and lipopolysaccharides (LPS; also known as endotoxin). These PAMPs initiate a myriad of immune responses through cell-surface receptors such as Toll-like receptors (TLRs) [1] as well as intracellular receptors, which leads to the formation of inflammasomes [2]. 

InvivoGen's E. coli OMVs have been purified from Escherichia coli BL21 using an optimized procedure, importantly providing lot-to-lot reproducibility.
Each batch of E. coli OMVs is thoroughly tested to characterize the OMV size and to ensure the activation of both TLR2 and TLR4 by the presence of lipoproteins and LPS, respectively.
Importantly, activation of the caspase 11-4/5 non-canonical inflammasome is confirmed using  THP1-HMGB1::Lucia™ cells, measuring the release of the alarmin HMGB1 due to inflammasome-mediated cell death. 

InvivoGen provides two grades of E. coli OMVs:

• E. coli OMVs (standard preparation) - recommended for in vitro studies

• E. coli OMVs InvivoFit™ - recommended for in vivo studies.

Specifically, E. coli OMVs InvivoFit™ are guaranteed sterile and have an endotoxin level >10⁵ EU/mg of OMVs.

References:

1. Kaparakis-Liaskos, M. & Ferrero, R.L., 2015. Immune modulation by bacterial outer membrane vesicles. Nat Rev Immunol. 15:375-387.
2. Russo, A.J. et al, 2018. Emerging insights into noncanonical inflammasome recognition of microbes. J Mol Biol. 430:207-216.

Specifications

E. coli OMVs

Source: Escherichia coli BL21

Specificity:  Caspase 11-4/5 inflammasome

Working concentrations: : 0.2 - 100 µg/mL (in vitro) and 10 - 100 µg/mouse (in vivo)

Quality Control:

• Size range: 35-60 nm

• Activation of TLR2 and TLR4 by E. coli OMVs has been confirmed using HEK-Blue™  TLR cellular assays.

• Inflammasome activation by E. coli OMVs has been determined by the induction of pyroptosis in THP1-HMGB1::Lucia™ cells.

E. coli OMVs InvivoFit™

Source: Escherichia coli BL21

Specificity: Caspase 11-4/5 inflammasome

Working concentrations: 0.2 - 100 µg/mL (in vitro) and 10 - 100 µg/mouse (in vivo)

Quality Control:

• E. coli OMVs InvivoFit™ are guaranteed sterile.

• Endotoxin levels:  >10⁵  EU/mg of OMVs

• Size range: 35-60 nm

• Activation of TLR2 and TLR4 by E. coli OMVs InvivoFit™ has been confirmed using HEK-Blue™  TLR cellular assays.

• Inflammasome activation by E. coli OMVs InvivoFit™ has been determined by the induction of pyroptosis in THP1-HMGB1::Lucia™ cells.

Contents

E. coli OMVs

• 100 µg E. coli OMVs (quantity of protein measured by a BCA protein assay)

• 1.5 mL of sterile endotoxin-free water

E. coli OMVs InvivoFit™

• 500 µg E. coli OMVs InvivoFit™ (quantity of protein measured by a BCA protein assay)

• 1.5 mL of sterile endotoxin-free water

 Product is shipped at room temperature

 Upon receipt product should be stored at -20°C

Details

Innate immune response activated by E. coli OMVs

Outer membrane vesicles (OMVs) are small, non-replicative, immunogenic spherical bodies secreted by both commensal and pathogenic Gram-negative bacteria such as E. coli [1]. OMVs contain components of the parent bacterium such as DNA, RNA, peptidoglycan, protein, toxins, and lipopolysaccharides (LPS), which act as pathogen-associated molecular patterns (PAMPs). PAMPs from OMVs interact with pattern recognition receptors (PRRs) expressed on the surface of host cells such as Toll-like receptors (TLRs), inducing both pro- and anti-inflammatory responses; a balancing act that can result in either pathogen clearance or bacterial survival [2]. Additionally, OMVs can be endocytosed and deliver their highly immunogenic cargo directly to the cytosol of the host cell, where a number of PAMPs can activate intracellular PRRs and lead to the formation of the caspase 11-4/5 inflammasome [3]. Ultimately, the activation of this complex results in pyroptotic cell death through the action of Gasdermin-D and the release of pro-inflammatory cytokines such as IL-1β and IL-18.

References:

1. Kulp, A. & Kuehn, M.J., 2010. Biological functions and biogenesis of secreted bacterial outer membrane vesicles. Annu Rev Microbiol 64:163-184.
2. Kaparakis-Liaskos, M. & Ferrero, R.L., 2015. Immune modulation by bacterial outer membrane vesicles. Nat Rev Immunol 15:375-387.
3. Vanaja, S.K. et al., 2016. Bacterial Outer Membrane Vesicles Mediate Cytosolic Localization of LPS and Caspase-11 Activation. Cell 165:1106-1119.

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