ImuXen® is a liposomal technology platform designed to improve the delivery and effectiveness of DNA, protein and polysaccharide vaccines.
Proof of concept preclinical studies with a number of vaccines have shown that ImuXen® technology can help to generate the rapid onset of protective immune responses, in some cases following just a single dose.
The advantages of ImuXen® for DNA, protein and polysaccharide vaccines include:
- Efficient delivery of vaccine antigens to the immune system
- Enhanced immune responses
- Protective immunity after a single injection
- Protection of vaccine against degradation during storage
- Rapid, simple and scalable manufacture
How does liposomal vaccine delivery work?
Liposomes are microscopic spheres typically consisting of a bi-layer of naturally occurring lipids with a central aqueous core. Xenetic’s proprietary techniques allow the rapid and simple entrapment of DNA, protein and polysaccharide antigens within the aqueous core of liposomes, creating vaccines that induce protective immunity through the generation of enhanced immune responses. Because the lipids used to create Xenetic’s liposomes occur naturally in nature and the antigens are entrapped within the liposomal core, ImuXen® vaccines greatly reduce the side effects associated with conventional vaccines, including minimising injection site reactions and reducing the risk of anaphylaxis.
Watch a video explaining our ImuXen® technology
How does ImuXen® improve liposomal vaccine delivery?
Although the use of liposomes to administer vaccines is not a new process, conventional liposomal vaccines are based on the delivery of DNA or protein antigens alone. This can produce weak or inappropriate immune responses and may require multiple doses to achieve effective immunity. In contrast, ImuXen® can deliver effective immunity following a single dose.
ImuXen® is based on proprietary techniques that allow the entrapment of vaccine antigens within liposomes with carefully defined and controlled characteristics. This process can be used to create and deliver DNA, protein and polysaccharide-based vaccines capable of generating enhanced immune responses.
Proof of concept preclinical studies have shown that the benefits of ImuXen® vaccines include:
- Reduction in the number of doses required
- Reduction in side effects
- Potential for oral administration of vaccines
- Potential for multiple vaccines to be delivered in the same injection
How does ImuXen® work with DNA-based vaccines?
A ground-breaking aspect of ImuXen® is the co-entrapment of a plasmid DNA along with the protein antigen it encodes within the same liposome. This is Xenetic’s proprietary ‘co-delivery’ technology. Studies have repeatedly shown that a single injection of a co-delivery formulation can generate faster and stronger immune responses than those obtained following multiple injections of liposomes incorporating either the plasmid DNA or the protein antigen alone or even if the two individual formulations are mixed and injected together. It is the co-delivery of the complimentary antigens within the same liposome that makes the key difference. This approach to vaccination mimics the way immunity is achieved by live viruses. In viral infections, the nucleic acids (DNA or in some cases, RNA) and the proteins they encode both contribute to the immune response against the virus.
Xenetic’s vaccines can be further advanced by coating ImuXen® liposomes with a sugar known as mannose. Mannose-coated liposomes are specifically targeted to cells of the immune system displaying receptors on their surface designed to recognise mannose molecules. This promotes uptake of the liposomes by these immune cells, further stimulating the 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 capable of inducing long-lasting protective immunity.
Conventional multivalent polysaccharide-based vaccines (such as pneumococcal vaccines) are usually administered as a mixture of polysaccharides derived from a specific number of strains of the infectious organism. Such vaccines are designed to protect against infection with the most common strains of the organism but typically produce immune responses that are only transient in adults and inefficient in infants. To achieve more lasting protective immune responses, a process known as conjugation is used to chemically attach 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 efficient and common to all polysaccharides. This involves the simple co-entrapment of each of the polysaccharide types together with a carrier protein in individual liposome preparations. These liposomal preparations are then pooled to provide a multivalent vaccine. Importantly, the requirement for any chemical conjugation is removed by the process of co-entrapment. Proof of concept studies have shown that multivalent polysaccharide vaccines made in this way are as efficacious as their chemically constructed counterparts.
