ImuXen®
ImuXen® is a group of liposomal technologies designed to improve the delivery and effectiveness of DNA, protein and polysaccharide vaccines.
Proof of concept preclinical studies with a variety of vaccines have shown that ImuXen® technology can help generate strong protective immune responses, in some cases with a single injected dose.
Scanning electro micrograph of liposomes. Artwork by Annie Cavanagh and David McCarthy
The potential advantages of ImuXen® for DNA, protein and polysaccharide vaccines include:
- Vaccine protection against degradation
- Efficient delivery of vaccines to the immune system
- Increased immune responses
- Protective immunity with a single injection
- Rapid, simple and scaleable manufacture
How does ImuXen® improve liposomal vaccine delivery?
ImuXen® can deliver immunity with a single vaccine dose.
Although the use of liposomes to administer vaccines is not a new process, conventional methods of liposomal vaccine delivery rely on a DNA or protein vaccine alone. This can produce inappropriate immune responses and require multiple repeat doses to achieve immunity.
ImuXen® is based on proprietary techniques that allow the liposomal co-entrapment of diverse vaccine antigens. This process is known as co-delivery and can be used to deliver DNA, protein and polysaccharide vaccines that generate stronger immune responses.
Proof of concept preclinical studies have shown that the benefits of ImuXen® for DNA, protein and polysaccharide vaccines include:
- Multiple vaccines delivered with a single injection
- Reduction in the number of doses required
- Reduction in side effects
- Potential for oral administration of vaccines
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How does liposomal vaccine delivery work?
Liposomes are microscopic spherules that consist of an aqueous core surrounded by bilayers composed of natural lipids. Liposomal vaccine formulation can minimize the side effects of vaccination, which can include injection site reactions and anaphylaxis.
Lipoxen’s proprietary techniques allow the rapid and simple formulation of DNA, protein and polysaccharide vaccines within the aqueous core of liposomes. ImuXen® technology has been adapted to produce liposome-based genetic (DNA) vaccines as well as polysaccharide vaccines that confer protective immunity through the generation of powerful immune responses.
How does ImuXen® work in DNA vaccines?
A ground-breaking aspect of ImuXen® is the co-entrapment of a plasmid DNA and the protein vaccine it encodes in the same liposome. This means that a single injection can generate much stronger immune responses than those obtained after multiple injections of liposomes incorporating the DNA or the protein vaccine alone.
This approach to immunisation mimics the way immunity is achieved in viral infections. In viral infections, both the viral DNA (or RNA) and the proteins it encodes contribute to the immune response against the virus. The approach has been further advanced by coating ImuXen® liposomes with a sugar (mannose) found in plasma proteins. Mannose targets ImuXen® liposomes to immune cells, which further stimulates immune responses to the vaccine.
How does ImuXen® work in polysaccharide vaccines?
ImuXen® co-delivery technology can also be used to create liposome-based polysaccharide vaccines that create longer-lasting protective immunity.
Conventional multivalent polysaccharide vaccines (such as pneumococcal vaccines) are usually administered as a mixture of polysaccharides covering a variety of strains of the infectious organism. Such vaccines typically produce immune responses that are only transient in adults and inefficient in infants. To achieve more lasting protective immune responses, a chemical process is used to conjugate each of the polysaccharides to a carrier protein.
Chemical conjugation requires complex and expensive technologies. However ImuXen® provides an improved method of formulating polysaccharide vaccines, and uses a co-delivery process which is simple, efficient and common to all polysaccharides. This involves co-entrapment of each of the polysaccharide types together with the carrier protein in individual liposome preparations. These liposomal preparations are then pooled to provide a multivalent vaccine.