New 'adjuvant' could hold future of vaccine development

Sep 14, 2009

Scientists at Oregon State University have developed a new "adjuvant" that could allow the creation of important new vaccines, possibly become a universal vaccine carrier and help medical experts tackle many diseases more effectively.

Adjuvants are substances that are not immunogenic themselves, but increase the when used in combination with a vaccine.

However, due to concerns about safety and toxicity, there's only a single vaccine adjuvant - aluminum hydroxide, or alum - that has been approved for human use in the United States. It's found in such common vaccines as hepatitis B and tetanus. But even though widely used, alum is comparatively weak and will only work with certain diseases.

The new adjuvant is based on nanoparticles prepared with lecithin, a common food product. In animal models, it helped protein antigens to induce an immune response more than six times stronger than when alum was used. Researchers also showed that the lecithin nanoparticles were able to help induce a reasonable antibody response after only one shot, whereas it took at least two shots for the alum adjuvant to work.

Based on their studies, researchers believe the lecithin nanoparticles have wide potential applications and possibly a good safety profile. Their findings were just published in the Journal of Controlled Release, a professional journal in the field of pharmaceutics, in work supported by the National Institute of Allergy and Infectious Diseases.

"In many cases, to make progress with vaccine development we need new adjuvants," said Zhengrong Cui, an assistant professor of pharmaceutics at OSU and corresponding author on the new study. "The material has to be safe, and lecithin is a common food product that's already widely used in pharmaceuticals. This new form of using lecithin nanoparticles as an adjuvant is promising and could become very important."

Vaccine development has always been difficult and at times controversial, Cui said, because of concerns about adverse effects when giving vaccines to healthy people.

Because of that, the U.S. Food and Drug Administration has been conservative about approving new vaccine adjuvants, he said. But even the safety issue is complex - to help avoid risk, new vaccines are based on purified compounds from microbes, but these provoke a very weak immune response and often need an adjuvant to boost them. Vaccines could be made based on dead or live attenuated microbes, but that would have a higher level of risk. The ultimate solution is new and improved adjuvants that help address both concerns about safety and efficacy.

Another problem, he said, is that the alum adjuvant that is common in some U.S. vaccines has very limited value in the development of many potential vaccines against viruses or tumors.

By contrast, the lecithin-based nanoparticle adjuvant is more effective. The extraordinarily small particles move easily to the lymphatic system that plays a key role in development of immune response, and they physically "look like" a pathogen to the immune system, which quickly gears up to fight them.

"Our early studies with laboratory animals seem to suggest that a based on the lecithin nanoparticle adjuvant would not only be more effective, but be tolerated by the body more readily than one using alum," Cui said. "Lecithin is very non-toxic, it's one of many compounds 'generally recognized as safe' by the FDA, and at the injection site we saw none of the nodules and tissue hardening you sometimes see with vaccines that use alum."

If the new adjuvant is ultimately shown to be safe and is approved following clinical trials, Cui said, it could become the basis for a revolution in the production of vaccines and serve as a universal carrier.

Source: Oregon State University (news : web)

Explore further: Secret of tetanus toxicity offers new way to treat motor neuron disease

add to favorites email to friend print save as pdf

Related Stories

Scientists discover how common vaccine booster works

May 21, 2008

In an online paper in the journal Nature, Yale University researchers funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, explain how a common ingredient in man ...

Tattooing improves response to DNA vaccine

Feb 07, 2008

A tattoo can be more than just a fashion statement – it has potential medical value, according to an article published in the online open access journal, Genetic Vaccines and Therapy.

Vaccines tested for use against bird flu

Mar 31, 2006

Human testing on a two potential vaccines against the H5N1 strain of bird flu has begun in Germany and Belgium, according to GlaxoSmithKline PLC.

Do vaccines cause autism, asthma and diabetes?

Jun 11, 2008

Almost 70% of parents who refuse to vaccinate their children do so because they believe vaccines may cause harm. Indeed vaccines have been blamed for causing asthma, autism, diabetes, and many other conditions--most of which ...

Recommended for you

Stroke damage mechanism identified

8 hours ago

Researchers have discovered a mechanism linked to the brain damage often suffered by stroke victims—and are now searching for drugs to block it.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

deatopmg
1 / 5 (1) Sep 15, 2009
will lecithin injection cause a long term inflammatory immune response to lecithin in the body just like injected squalene?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.