Engineered Pathogen-like Particle Subunit Vaccines Induce Robust, TH1-Biased Immunity

Bacterial outer membrane vesicles (OMVs) derived from the probiotic E. coli strain Nissle 1917 (EcN) were engineered as recombinant subunit vaccine delivery carriers. Green fluorescent protein (GFP) was selected as the model antigen and recombinantly expressed as a fusion chimera with the surface-displayed enterotoxin ClyA in hypervesiculating EcN. Vaccination in a murine model combined with additional in vitro studies allowed for thorough assessment of EcN OMV-facilitated immunostimulation and the resulting anti-GFP response. Results indicate the induction of a robust, TH1-biased immune response, making the EcN OMVs potentially ideal for vaccine applications.