Team unlocks key to safer vaccines
June 15th, 2007
A team from the University of Louisville has found clues that explain how one vaccine additive works to produce faster, stronger and longer lasting immunity than the vaccine alone.
The team’s results, published June 14 in Science magazine, show that the immune systems of mice injected with an adjuvant (a vaccine additive that boosts immune function) called Monophosphoryl Lipid A (MPLA) developed strong immune responses without toxic side effects. Researchers found evidence that MPLA has unexpected anti-inflammatory properties.
“These results have important implications for future vaccine development with the potential to help millions avoid infectious disease,” said Thomas Mitchell, associate professor of microbiology and immunology and Barnstable-Brown Chair in Diabetes Research.
“One of the key challenges in developing vaccines is finding a formula that boosts immunity while avoiding harmful side effects. Current vaccines maximize patient safety, but may not maximize immunity,” Mitchell said.
The team measured the immune response in mice treated with MPLA and a related compound, LPS, which is not approved for human use due to toxic side effects. They showed that MPLA matches LPS in stimulating the multiplication of cells that can recognize and destroy harmful bacteria and viruses.
Those cells, in turn, are strong producers of a protein that creates a feedback loop allowing the immune cells to proliferate and attack the source of infection. At the same time, MPLA does not seem to have the toxic side effects seen with the use of LPS.
Alum is the only vaccine additive currently approved for use in the United States. Although it is widely viewed as a safe agent, it does not maximize immunity.
The team includes five researchers from UofL’s Institute for Cellular Therapeutics and one from the School of Dentistry’s Oral Health and Systemic Disease research group. According to Mitchell, the researchers hope that their results will lead to a new generation of vaccines that will allow patients to be better protected from disease for longer periods of time and with fewer injections.
