BiOMViS vaccine platform is based on Outer Membrane Vesicles (OMVs) released by a non-pathogenic E. coli derivative (E. coli BL21Δ60) created by a Synthetic Biology approach. The amazing properties of this new strain, also nicknamed Vaccinobacter vesiculosus, can be summarized as follows:
- It carries the inactivation of 60 genes encoding proteins found in OMVs released by wild type E. coli BL21. As a consequence of such deletions, E. coli BL21Δ60-derived OMVs (OMVsΔ60) are “proteome minimized”, being deprived of a large quantities of endogenous proteins.
- The lipopolysaccharide biosynthetic pathway of E. coli BL21Δ60 has been genetically modified to reduce the potential reactogenicity of Lipid A. Such modification makes OMVsΔ60 fully compatible with human applications, as judged by their safety profile (TLR4 agonist activity and IL-6 release assay) comparable with OMV-based vaccines currently in the clinics.
- E. coli BL21Δ60 releases high quantities of OMVs, rendering the strain an ideal cell factory of inexpensive and easy-to-produce vaccines.
- By using innovative cloning strategies, E. coli BL21Δ60 can be efficiently engineered to release OMVs fully packed with heterologous antigens. Thanks to absence of endogenous proteins, engineered OMVsΔ60 elicit optimized antibody and cell-mediated immunity against heterologous antigens in animal models.
|Figure 1 – SSDS-PAGE analysis of engineered OMVs decorated with different heterologous antigens – E. coli strains featuring hyper-visiculation phenotype were genetically modified using different cloning strategies aimed at delivering foreign antigens to the OMV compartment. Engineered OMVs were purified from the culture supernatants and total OMV proteins were separated by SDS-PAGE. Arrows indicate the protein bands corresponding to the heterologous antigen expressed in each OMV preparation.|