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Chemists synthesize molecule
that helps body battle cancers, malaria
Kloeppel, Physical Sciences Editor
photo to enlarge
by Kwame Ross
Y. Gin, a professor of chemistry, and his colleagues
have synthesized QS-21A, a medically important molecule
that helps the body battle disease.
Ill. — The first synthesis of QS-21A, a medicinally important
molecule that helps the body battle disease, has been achieved by chemists
at the University of Illinois at Urbana-Champaign.
In clinical trials, QS-21A has been shown to significantly improve the
body’s immune response in vaccine therapies against aggressive
diseases such as melanoma, breast cancer, small-cell lung cancer, prostate
cancer, HIV-1 and malaria. An extract from the bark of the South American
tree Quillaja saponaria Molina, QS-21A is available only in small quantities.
“Now that we have synthesized this remarkable molecule and confirmed
its structure, we are in a position to examine how it works and investigate
ways to improve its performance,” said David Y. Gin, a professor
of chemistry at Illinois.
Gin and his collaborators describe their work in a paper that has been
accepted for publication in the Journal of the American Chemical Society,
and posted on its Web site.
An extremely powerful adjuvant, QS-21A enhances the potency of antigens
introduced in the body to elicit an immune response, allowing for lower
vaccine doses with greater effectiveness. The molecule could therefore
save patients money on expensive drugs and stretch limited supplies
of antigens and vaccines.
Gin and his collaborators are now exploring ways to improve the molecule.
By investigating structure activity relationships, they want to strip
away nonessential structures, leaving a simpler and more potent core.
“One frequent problem encountered with vaccines is ensuring that
the vaccine is potent enough to elicit a strong immune response,”
Gin said. “We will continue looking for ways to produce new molecules
similar to QS-21A that will enhance the body’s natural immune
response to eradicate diseases.”
The research team included postdoctoral research associates Pengfei
Wang, Mauricio Navarro-Villalobos and Bridget D. Rohde, and graduate
student Yong-Jae Kim. The work was funded by the National Institutes