By Laura Freeman

After seeing the lethal potential of a worldwide pandemic and the promise of immune therapy in the fight against relentless killers like cancer, the value of adjuvants that can help the immune system work better are a highly valued addition to the medical toolbox.

Unfortunately, the go-to adjuvant used in current vaccine and immune system research, QS21, is derived from the bark of a tree that is in short supply. It is found only in a limited area of Chile, harvesting the bark kills the adult trees now available, and even with an effort to farm plantations of new saplings, the simple truth is that trees can’t grow fast enough. 

There wouldn’t be enough of the precious natural ingredients to boost a dose of vaccine to save everyone if another major epidemic occurs in the next few years. Even coming up with enough of the rare, expensive adjuvant to test new immune therapies against cancer and develop new vaccines could be a challenge.

Fortunately, here in Birmingham, in the lab of UAB chemistry professor Pengfei Wang, PhD a naturally occurring molecule derived from an abundant, inexpensive source has been identified.

“In addition to being effective in increasing the response of the immune system to vaccines, the molecule we are working with is also more stable and less likely to have toxicity issues. In fact, the plant is derived from an Asian vegetable people have been eating for centuries. The seeds it comes from are so plentiful that when we ordered a supply online, we found it available by the pound through Wal-mart or at lower bulk prices from several sources,” Wang said.

Known by gardeners and Asian vegetable farmers by the common name of bitter gourd, the plant with the helpful molecules in known by scientists by its Latin name, momordica cochinchinensis. As a food, it’s an acquired taste due to the extreme bitterness, but it is known as a good source of several nutrients and it has been used as a folk remedy by several cultures. What attracted Wang’s interest was the fact that it contained saponin molecules.

A saponin is a plant like soapwart that can be used like a soap to clean or break up oils. While the exact mechanisms of how adjuvants work to strengthen immune response is yet to be made fully clear, Wang has found that plants with saponins tend to be good candidates for study of their potential for developing into adjuvants.

“We formed the company Adjuvax LLC as a way to make saponin-based adjuvants that show high potential available to research teams developing novel vaccines and immunotherapy drugs,” Wang said. “We won a grant from Innovate Alabama, moved into lab facilities at the Southern Research biotech incubator, Station 41, and received a contract from the NIH to develop the saponin-based adjuvant.

“I continue to work as a full time chemistry professor at UAB, but I’ve been putting all my free moments into serving as Chief Scientific Officer at Adjuvax. Our goal is to continue identifying and developing potential adjuvants so we can can offer novel vaccine and immunotherapy developers a source they can turn to for a variety of adjuvants that can be tested in different combinations to identify the most effective custom adjuvant for the particular vaccine or therapy they are working to make available.”

Effective, safe and plentiful adjuvants can make a tremendous difference in protecting public health and helping people recover from immune-related diseases. They could potentially reduce the amount of antigen required in a dose, reduce or eliminate the need for follow-up doses, and possibly foster immunity that lasts over a longer period. Eventually, insights gained from adjuvant research may provide the keys that unlock a better understanding of immune system-related conditions, from cancer to arthritis to allergies.

Most of all, anything with the potential to improve protection of a world’s population against another pandemic will be welcome—not just a defense against something like COVID, but also like the flu pandemic of 1918 that would be likely to kill far more with modern transportation to carry it far and wide.

Fears of an Avian flu outbreak continue to be the topic of concern for public health authorities with many stating it’s not a matter of if, but when, with more frequent animal to human cases reported.  Before it makes the jump from human to human, we can wish vaccine and adjuvant researchers all success possible.