An OMV-Based Nanovaccine Confers Safety and Protection against Pathogenic Escherichia coli via Both Humoral and Predominantly Th1 Immune Responses in Poultry

Abstract

Avian pathogenic Escherichia coli (APEC) infection in poultry causes enormous economic losses and public health risks. Bacterial outer membrane vesicles (OMVs) and nano-sized proteolipids enriched with various immunogenic molecules have gained extensive interest as novel nanovaccines against bacterial infections. In this study, after the preparation of APEC O2-derived OMVs (APEC_OMVs) using the ultracentrifugation method and characterization of them using electron microscopy and nanoparticle tracking analyses, we examined the safety and vaccination effect of APEC_OMVs in broiler chicks and investigated the underlying immunological mechanism of protection. The results showed that APEC_OMVs had membrane-enclosed structures with an average diameter of 89 nm. Vaccination with 50 μg of APEC_OMVs had no side effects and efficiently protected chicks against homologous infection. APEC_OMVs could be effectively taken up by chicken macrophages and activated innate immune responses in macrophages in vitro. APEC_OMV vaccination significantly improved activities of serum non-specific immune factors, enhanced the specific antibody response and promoted the proliferation of splenic and peripheral blood lymphocytes in response to mitogen. Furthermore, APEC_OMVs also elicited a predominantly IFN-γ-mediated Th1 response in splenic lymphocytes. Our data revealed the involvement of both non-specific immune responses and specific antibody and cytokine responses in the APEC_OMV-mediated protection, providing broader knowledge for the development of multivalent APEC_OMV-based nanovaccine with high safety and efficacy in the future.

Avian Pathogenic Escherichia coli (APEC): An Overview of Virulence and Pathogenesis Factors, Zoonotic Potential, and Control Strategies

“…Various vaccine candidates, mostly live-attenuated and recombinant vaccines, have been investigated to protect chickens against APEC infections [ 5 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 ]. Table 3 provides the summary of vaccines tested to date along with their main findings.…”

Dietary Eucommia ulmoides Extract Alleviates the Effect of Cold Stress on Chick Growth Performance, Antioxidant and Immune Ability

“…The liver, heart, spleen, thymus, bursa of Fabricius (BF), duodenum, and musculature were separated and sucked with filter paper. After the blood had dried, their weights were valued, and the organ indexes were then calculated as follows [ 48 ]: Organ index = organ weight (g)/body weight (g) × 100%.…”

Biomimetic Nanoparticles Coated with Bacterial Outer Membrane Vesicles as a New-Generation Platform for Biomedical Applications

“…Despite the fewer research studies on bacterial membrane-coated NPs than those on mammalian-derived membrane-coated NPs, the former has shown remarkable promise for further application-oriented studies in terms of following aspects. First, OMVs could be a novel and potentially ideal source of cellular membrane for coating NPs in applications requiring the activation of pathogen-associated innate and adaptive immune responses [28,29] as well as the prevention of inflammation caused by commensal bacteria resided in the gut [30]. This promising application comes from the fact that OMVs include a high content of immunogenic proteins and adjuvants that can be used to modulate the immune system of target hosts [31].…”