Contact: Will Sansom, (210) 567-2579

Yan Xiang, Ph.D., (right) and Xiangzhi Meng, Ph.D., of the Department of Microbiology and Immunology, study the workings of poxviruses, some of which are among the most dreaded bioterrorism agents.
Printer Friendly Format

SAN ANTONIO (Jan. 13, 2009) — Like an enemy soldier disabling a guard to mask an invasion, the action of a deadly poxvirus overcoming a body’s defense mechanism was revealed in crystalline form by researchers at the UT Health Science Center San Antonio and Oklahoma State University.

“In essence, the poxvirus protein ties up and gags this sentry so no alarm is sent,” said study senior co-author Yan Xiang, Ph.D., assistant professor of microbiology and immunology at the UT Health Science Center. The new crystal structure reveals more about how the poxvirus protein is able to do this.


Poxviruses among most dangerous bioterrorism agents
Poxviruses, which cause smallpox and other infections, including the emerging human monkeypox, are a family of viruses that rank among the world’s most feared bioterrorism agents. Although the human body’s immune system can successfully fend off many disease agents, it is often ineffective against poxviruses, because these viruses employ an arsenal of proteins to disarm many infection-fighting proteins in the human immune system.

A rare snapshot of a poxvirus protein, caught in the middle of its act against a human immune molecule called IL-18 (short for interleukin-18), was revealed recently through a 3-D crystal structure the scientists “captured.” The study and resulting “snapshot” is in the Dec. 30, 2008, print edition of the Proceedings of the National Academy of Sciences.

Clues may lead to inhibitors and vaccines against poxviruses
“Determining the crystal structure is an important step toward designing an inhibitor for this poxvirus protein as a treatment for disease caused by a poxvirus,” Dr. Xiang said. “Drugs against poxviruses are greatly needed, as there is currently no effective therapy against poxviruses and the current vaccine has many side effects.”

The structure can also help the development of effective inhibitors against IL-18 to treat autoimmune diseases in which IL-18 is too active, Dr. Xiang added. Inhibitors against proteins similar to IL-18 are being used in clinics to treat rheumatoid arthritis.

Team approach solves crystalline puzzle
Dr. Xiang and Junpeng Deng, Ph.D., a structural biologist at Oklahoma State University, are the co-corresponding authors of the paper. “A lot of credit goes to Dr. Deng and his group,” Dr. Xiang said. “Xiangzhi Meng, Ph.D., a talented research scientist in my lab, also contributed significantly and deserves praise for her hard work and dedication.”

Dr. Xiang joined the UT Health Science Center in 2002 after a postdoctoral fellowship at the National Institutes of Health (NIH), where he discovered the poxvirus proteins that bind IL-18. Dr. Xiang recently was awarded a four-year, $1.3 million NIH grant to study the same poxvirus proteins with the goal of developing better vaccines and therapeutics for poxviruses.

# # #
The University of Texas Health Science Center at San Antonio is the leading research institution in South Texas and one of the major health sciences universities in the world. With an operating budget of $668 million, the Health Science Center is the chief catalyst for the $16.3 billion biosciences and health care sector in San Antonio’s economy. The Health Science Center has had an estimated $36 billion impact on the region since inception and has expanded to six campuses in San Antonio, Laredo, Harlingen and Edinburg. More than 25,600 graduates (physicians, dentists, nurses, scientists and other health professionals) serve in their fields, including many in Texas. Health Science Center faculty are international leaders in cancer, cardiovascular disease, diabetes, aging, stroke prevention, kidney disease, orthopaedics, research imaging, transplant surgery, psychiatry and clinical neurosciences, pain management, genetics, nursing, dentistry and many other fields. For more information, visit www.uthscsa.edu.