University of Pittsburgh Graduate School of Public Health researchers are expanding their efforts to develop a vaccine for a deadly tropical virus by looking in their own backyard.
Dengue fever, a mosquito-borne illness that is contracted by as many as 100 million people worldwide annually, has re-emerged in the U.S. and is endemic in Puerto Rico, spurring increased demand for a vaccine. To aid that effort, Pitt Public Health researchers are putting out the call for Pittsburghers who have spent time in tropical areas to give a small blood sample.
“While some people who contract dengue virus suffer severe hemorrhagic bleeding, many more have little to no symptoms,” said Paolo Piazza, Ph.D., research assistant professor in the Department of Infectious Diseases and Microbiology at Pitt Public Health. “By analyzing the blood of people who have lived in areas afflicted by dengue, we hope to learn more about the immune functions that give protection against severe disease.”
By looking at a type of white blood cell that kills cells infected by viruses, the researchers are investigating whether the white blood cells express alleles – or genetic variations – that give increased immunity to dengue virus.
If the alleles are present, the researchers infect the blood sample (not the volunteer participant) with the virus. They then isolate the short protein fragments, called peptides, which bind to the white blood cells and trigger an immune response. This gives scientists the tools necessary to make a vaccine.
Other efforts are underway to develop a dengue vaccine, with pharmaceutical giant Sanofi Pasteur leading the pack. Unfortunately, the Sanofi vaccine was dealt a blow late last year when it was found to be only 30 percent effective in its first large clinical trial, with the disappointing results reported in The Lancet, a medical journal.
“Dengue fever is a very difficult disease for which to develop a vaccine because the immune response to the virus is so complicated,” said Dr. Piazza. “There are four different, closely related types of dengue virus, and it seems that infection with one type predisposes people to more severe illness if infected with a different type a few years later. This is why it is critical that we gain a thorough understanding of how the immune system fights this virus.”
Dengue virus is common in Central America, South America, Mexico, Southeast Asia, the Pacific Islands, India, Northern and Eastern Australia, Central Africa, the Caribbean, Puerto Rico and Guam. It also re-emerged a few years ago in the Florida Keys, where it hadn't been seen in 60 years.
“Pittsburgh has a strong international community,” said Diana Campbell, B.S., a lab technician at Pitt Public Health. “We're confident that there are people from tropical areas now living here who, by giving a small blood sample and answering some simple background questions, could play a pivotal role in the global fight on dengue.”
Study participants’ identities will be kept anonymous, and they will be compensated for their time. For more information, contact Diana Campbell, Emily Frost or Dr. Paolo Piazza by at 412-648-2940 or email at
paolo@pitt.edu.
8/08/2013