Adjuvants are substances that are used to increase the immune response warranted by the immune system when used in combination with a vaccine. But the adjuvants are not themselves immunogenic.
So far due to safety concerns there is only one adjuvant that has been approved for human use in the united states. This is aluminum hydroxide (alum), which is used in vaccines for tetanus and hepatitis B. Still the use of alum will only work with certain diseases and mostly very weakly.
This is where the research team from the Oregon State University step in with their new nanoparticle based adjuvant. There adjuvant is based on nanoparticles prepared with lecithin, which is a common food product.
Lecithin is a group of fatty substances that are found in many animal and plant tissues, most commonly associated with egg yolk. It is regarded as a non-toxic surfactant.
In animal studies lecithin was shown to assist protein antigens to warrant an immune response six times more potent then when alum was used. Moreover it was shown that the lecithin adjuvant allowed a reasonable immune response with only one vaccination jab. Whereas with the use of alum it would take 2-3 shots to warrant the same response.
Based on these results, researchers believe the lecithin nanoparticles adjuvant has great potential for being used in many applications with a good safety profile.
The key issue with designing adjuvants is safety. It is always of the upmost importance that any healthy person receiving a vaccination should not see adverse effects from that vaccine. For this reason the U.S. FDA has always been very conservative with approval of any new vaccine adjuvants.
The belief is that the alum adjuvant has very limited value especially for vaccines against tumors or viruses. By stark contrast the lecithin nanoparticle adjuvant is far more effective. As the incredibly small particles it is made up of can move easily to the lymphatic system, which is key to creating the immune response needed to infer future protection to the individual.
At this time the animal studies have shown that lecithin seems to be tolerated well even more so then alum. If the adjuvant were to be shown safe following clinical trials it could revolutionize vaccine production – CT