Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

St. Jude develops vaccine against potential pandemic influenza virus H5N1 using reverse genetics

03.04.2003


Special modification of reverse genetics created at St. Jude allowed vaccine to be custom-made within weeks of emergence of virus



Scientists at St. Jude Children’s Research Hospital announced today the development of a vaccine against H5N1, a new lethal influenza virus that triggered the World Health Organization (WHO) to declare a pandemic alert in February 2003.

The virus appeared in birds in Hong Kong late last year and subsequently killed one of two infected people with rapidly progressive pneumonia in the past month. St. Jude developed the vaccine in only four weeks from the time it received the H5N1 sample from colleagues in Hong Kong.


The announcement comes at a time when a second, as-yet-unidentified virus, has taken several lives around the world. The unknown virus, which causes severe acute respiratory syndrome (SARS), appears to have originated at the same time and in the same place as the new "flu."

The development of the initial ("seed") batch of H5N1 vaccine is significant because humans do not have a natural immunity to the virus, according to Robert Webster, Ph.D., a member of the Department of Infectious Diseases at St. Jude. Rather, humans appear to become infected through contact with chickens and other birds. In the past the virus killed only the chickens it infected. But the new variant of H5N1 also killed many kinds of wild birds, which is unusual.

If H5N1 acquires the ability to pass from human to human, there would be the potential for concern similar to that for SARS, according to Webster.

"It’s likely there were two things that prevented the 1997 poultry influenza outbreak in Hong Kong from becoming more deadly--its inability to spread from human to human and the slaughter of more than 1.5 million chickens and other birds in the open-air markets of Hong Kong, which eliminated the source of the virus," Webster said. "In fact, the sudden appearance of SARS in the same region of the world is just another warning that the large populations of people and poultry in this region are a potential source of viruses."

Webster is the director of the WHO’s U.S. Collaborating Center at St. Jude that studies animal influenza viruses. It is the only WHO laboratory that focuses on the transmission of animal viruses to humans.

Webster’s laboratory has sent the seed H5N1 vaccine to the Centers for Disease Control in Atlanta and the World Influenza Center in London for further testing, in preparation for initial Phase I and Phase II trials in humans. "It’s important to move right along with these trials in case the virus begins spreading from person to person," Webster says. Led by Richard Webby, Ph.D., and Daniel Perez, Ph.D., the St. Jude laboratory team successfully modified a technique called reverse genetics to permit them to develop the H5N1 vaccine so quickly. Using the samples of H5N1 obtained from Hong Kong, Webby mixed two genes from H5N1 with six genes from a second virus (A/PR8/34)[H1N1]). H1N1 is a rapidly growing "master" strain of virus commonly used to make vaccines.

The genes from flu viruses produce proteins called HA and NA, which are on the surface of the virus, in full "view" of the immune system. Webby took the modified gene for HA and the NA from H5N1 and mixed them inside a cell with six genes from H1N1. The HA gene was modified to abolish its ability to cause disease and therefore made it safer to use in the vaccine.

The genes mixed together, and the resulting vaccine virus produced in the cell thus carried HA and NA from H5N1. But because of the alterations to the HA, and the rest of the genes being derived from H1N1, the new virus vaccine cannot cause disease. Rather, it can only stimulate the immune system to respond to H5N1.

"The St. Jude vaccine is like a gun without ammunition," said Elaine Tuomanen, M.D., director of the St. Jude Department of Infectious Diseases. "The vaccine looks deadly enough for its HA and NA proteins to alert the immune system. But in reality, it’s carrying blanks that can’t cause disease."

Key to the quick success in developing the vaccine was the on-campus availability of GMP (Good Manufacturing Practices) facilities, which are equivalent in quality to those used by pharmaceutical companies to make biological agents such as vaccines. In addition, the centralization of genetic analysis and other molecular biology work, performed in the Hartwell Center for Bioinformatics and Biotechnology at St. Jude, greatly accelerated the process of building the vaccine components.

"We’ve been lucky twice with H5N1--once in 1997 and once so far during this current outbreak--in not experiencing human-to-human transmission," Webster says. "But the mixing bowl in Hong Kong is still stirring up new variations of familiar viruses. Although we just made a vaccine against one of that mixing bowl’s nasty viral brews, SARS shows us there’s always another threat down the road."

St. Jude Children’s Research Hospital St. Jude Children’s Research Hospital, in Memphis, Tennessee, was founded by the late entertainer Danny Thomas. The hospital is an internationally recognized biomedical research center dedicated to finding cures for catastrophic diseases of childhood. The hospital’s work is supported through funds raised by ALSAC. ALSAC covers all costs not covered by insurance for medical treatment rendered at St. Jude Children’s Research Hospital. Families without insurance are never asked to pay. For more information, please visit http://www.stjude.org.


###

Bonnie Cameron | EurekAlert!
Further information:
http://www.stjude.org/

More articles from Health and Medicine:

nachricht World first: Massive thrombosis removed during early pregnancy
20.07.2017 | Universitätsspital Bern

nachricht Therapy of preterm birth in sight?
19.07.2017 | Universitätsspital Bern

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>