New vaccine delivery system 'incites stronger immune response'

A new way of delivering vaccines could increase the potency of medications that contain proteins created by the disease-causing bacterium or virus. Researchers have found a new way to deliver this type of vaccine, which can help reduce the risks and effectiveness of medications for fighting diseases.

Many types of vaccines make use of a disabled or killed version of the virus they are designed to fight, such as the vaccines for measles, influenza and polio. Unfortunately, this vaccine is not suitable for treating certain diseases as they can be too risky or inefficient.

The safer type of vaccine are those that make use of small extracts of proteins that are produced by the viruses or bacteria they are treating. This approach has found to present less risks and has been effective for a number of different disease, however; in some cases they don't result in a strong enough response.

Researchers from the Massachusetts Institute of Technology (MIT) have found a new way in which these vaccines can be delivered to promote a better response. By getting the vaccines to latch onto the protein albumin, they are delivered to the lymph nodes, which creates a better response from the immune system.

Darrell Irvine, professor of biological engineering and of materials science and engineering at MIT, said: "The lymph nodes are where all the action happens in a primary immune response. T cells and B cells reside there, and that's where you need to get the vaccine to get an immune response. The more material you can get there, the better."

According to the researchers, this approach to vaccine delivery could be effective for the treatment of HIV and for inciting the body's own immune system to attack tumour cells. 

The scientists based their approach to vaccine delivery on a procedure that is currently used for targeting imaging dyes to lymph nodes, called sentinel lymph node mapping. In this procedure, the dye binds to the albumin which then means it builds up in the lymph nodes.

To build on this procedure, researchers looked at developing vaccines that will effectively bind to the protein and so be transported to the lymph nodes. Albumin's main function is to transport fatty acids within its binding pockets, so the researchers developed vaccine peptides that had a fatty tail, or lipid.

When tested on mice, vaccines that had been developed to fight melanoma, HIV and cervical cancer were found to evoke an immune response that was between five and ten times stronger than the response triggered by peptide vaccines alone.