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Tuesday, 29 October 2013

A liposomal cocktail, a novel nanosystem for vaccine delivery in aquaculture

ICN2 and IBB researchers have published in Plos One journal a novel liposome-based nanocarrier capable of stimulating fish innate immune system.

The development of sustainable aquaculture, a strategic sector to feed the ever-increasing human population, relies on disease prevention through the implementation of preventive immunostimulation and effective vaccination strategies. In such a context, liposomes are hollow spherical, safe and well-tolerated assemblies formed by a single lipid bilayer or multiple concentric bilayers that can be tailored (via selecting their composition, size, charge, etc.) to efficiently entrap a wide variety of immunostimulants and vaccines. Also, liposomes have been proven to act as adjuvants to potentiate immune responses alone and to be rapidly cleared from sites of administration, being preferentially distributed among macrophages.

The encapsulation of immunostimulants and vaccines in lipidic systems provides the advantage of increasing their stability and protection, thus enhancing their immune response and disease protection, and opening up the possibility to design more efficient immunostimulant-vaccine cocktails. Taking into account these excellent properties and since liposomes can be stable in solution or be dried, new opportunities are available to aquaculture to use such systems as new immunostimulant vehicles, which could be administered either dissolved in water (immersion bath), by injection, or orally via coated-food.

In this context, a team of researchers from the Institut Catala de Nanociencia i Nanotecnologia (ICN2) and the Institut de Biotecnologia i de Biomedicina (IBB-UAB), composed of PhD student Angels Ruyra, Dr Mary Cano-Sarabia, Prof Simon A. MacKenzie, Dr Nerea Roher and Prof Daniel Maspoch, have developed a novel liposomal immunostimulant cocktail to stimulate two potent innate immune pathways virtually present in all fish species.

The work has been published in Plos One journal under the title “A Novel Liposome-Based Nanocarrier Loaded with an LPS-dsRNA Cocktail for Fish Innate Immune System Stimulation”. In the article, the researchers report a new 125 nm-in-diameter unilamellar liposome-encapsulated immunostimulant cocktail containing crude lipopolysaccharide (LPS), from E. coli, and polyinosinic:polycytidylic acid [poly (I:C)], a synthetic analog of dsRNA virus. This liposomal carrier showed high encapsulation efficiencies and low toxicity not only in vitro using three different cellular models but also in vivo using zebrafish embryos and larvae. They showed that such liposomal LPS-dsRNA cocktail is able to enter into contact with zebrafish hepatocytes (ZFL cell line) and trout macrophage plasma membranes, being preferentially internalized through caveolae-dependent endocytosis, although clathrin-mediated endocytosis in ZFL cells and macropinocytocis in macrophages also contribute to liposome uptake. They also demonstrated that this liposomal LPS-dsRNA cocktail elicits a specific pro-inflammatory and anti-viral response in both zebrafish hepatocytes and trout macrophages. The design of a unique delivery system with the ability to stimulate two potent innate immunity pathways virtually present in all fish species represents a completely new approach in fish health.

Funding: This work was supported by the Fundación Ramon Areces (2010) and the Fundació Amics de la Universitat Autonoma de Barcelona-Programa Aposta (2011). NR wishes to thank the Ministry of Industry and Competitiveness (Spain) for the Ramón y Cajal grant.

For more information, please contact:

Prof Daniel Maspoch - ICREA Research Professor and Group Leader

Supramolecular NanoChemistry & Materials Group (NANOUP, visit www.nanoup.org)

Tel: +34 937 374 634

E-mail: daniel.maspoch@icn.cat

Link to the Plos One journal article: A Novel Liposome-Based Nanocarrier Loaded with an LPS-dsRNA Cocktail for Fish Innate Immune System Stimulation