H5N1 vaccine could be basis for life-saving stockpile

June 19, 2006

Scientists at St. Jude Children's Research Hospital have announced that a vaccine they developed a few years ago against one antigenic variant of the avian influenza virus H5N1 may protect humans against future variants of the virus. Vaccines based on this model might therefore be suitable for stockpiling for use during a pandemic (worldwide epidemic) until a new vaccine could be developed specifically against the variant causing the outbreak, the researchers said. An antigen is a molecule that stimulates production of antibodies by the immune system.

A prepublication report on the study appears in the online issue of Journal of Infectious Diseases (JID).

The researchers showed that the vaccine completely protected ferrets from a lethal nasal infection against not only the original virus the vaccine was made to thwart, but also against a newer variant that has already proved fatal to humans. The ferrets experienced a more significant reduction of virus multiplication than otherwise would have occurred, the researchers reported. Moreover, the infections failed to spread out of the upper respiratory tract to the lungs or brain.

"These findings are especially significant because ferrets are known to be an excellent and accurate model of influenza infection and immune response in humans," said Elena Govorkova, Ph.D., a staff scientist in the Department of Infectious Diseases at St. Jude. "Restricting the infection to the upper respiratory tract is important since in humans the virus has been isolated from specimens taken from the cerebrospinal fluid, feces, throat and blood serum. Therefore, limiting the spread of virus in an infected human is crucial to saving that person's life." Govorkova is the lead author of the JID paper and led the research team conducting the study.

The team also showed that the optimal strategy for vaccination of immunologically naïve individuals will be the use of two doses, which in the ferrets triggered more antibody protection than a single dose. Immunologically naïve individuals are those whose immune systems have not been stimulated to respond to a particular antigen.

The St. Jude study was the first one to show cross-reactive immunity against current H5N1 variants in ferrets, according to Robert Webster, Ph.D., a member of the Infectious Diseases department and holder of the Rose Marie Thomas Chair at St. Jude. Webster is an internationally renowned expert on avian influenza viruses and is senior author of the report in JID.

Cross-reactive immunity is the protection that a virus vaccine confers against not only the same virus, but also against variants of the original virus. "Such cross-protection would allow the use of a stockpiled vaccine until a vaccine against the specific variant causing the outbreak is developed," Webster said. "So our success with ferrets is extremely promising news."

Using reverse genetics, the team mixed genes from a safe, laboratory bird flu virus with a gene for the hemagglutinin (HA) protein from the H5N1 virus isolated in Hong Kong. The virus uses the HA proteins on its surface to infect cells in the respiratory tract. The resulting vaccine had the outside appearance of a dangerous virus that would stimulate the immune system, but the inside genes of a harmless variety of virus that could not cause disease. The St. Jude team was the first to use reverse genetics to make a vaccine against H5N1 that moved out of the laboratory and into clinical trials: http://www.stjude.org/media/0,2561,453_5484_4638,00.html.
-end-
Other authors of the study include Richard Webby, Jennifer Humberd and Jon Seiler, all of St. Jude.

This work was supported in part by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health and ALSAC.

St. Jude Children's Research Hospital
St. Jude Children's Research Hospital is internationally recognized for its pioneering work in finding cures and saving children with cancer and other catastrophic diseases. Founded by late entertainer Danny Thomas and based in Memphis, Tenn., St. Jude freely shares its discoveries with scientific and medical communities around the world. No family ever pays for treatments not covered by insurance, and families without insurance are never asked to pay. St. Jude is financially supported by ALSAC, its fund-raising organization. For more information, please visit www.stjude.org.

St. Jude Children's Research Hospital

Related Infectious Diseases Articles from Brightsurf:

Understanding the spread of infectious diseases
Physicists at M√ľnster University (Germany) have shown in model simulations that the COVID-19 infection rates decrease significantly through social distancing.

Forecasting elections with a model of infectious diseases
Election forecasting is an innately challenging endeavor, with results that can be difficult to interpret and may leave many questions unanswered after close races unfold.

COVID-19 a reminder of the challenge of emerging infectious diseases
The emergence and rapid increase in cases of coronavirus disease 2019 (COVID-19), a respiratory illness caused by a novel coronavirus, pose complex challenges to the global public health, research and medical communities, write federal scientists from NIH's National Institute of Allergy and Infectious Diseases (NIAID) and from the Centers for Disease Control and Prevention (CDC).

Certain antidepressants could provide treatment for multiple infectious diseases
Some antidepressants could potentially be used to treat a wide range of diseases caused by bacteria living within cells, according to work by researchers in the Virginia Commonwealth University School of Medicine and collaborators at other institutions.

Opioid epidemic is increasing rates of some infectious diseases
The US faces a public health crisis as the opioid epidemic fuels growing rates of certain infectious diseases, including HIV/AIDS, hepatitis, heart infections, and skin and soft tissue infections.

Infectious diseases could be diagnosed with smartphones in sub-Saharan Africa
A new Imperial-led review has outlined how health workers could use existing phones to predict and curb the spread of infectious diseases.

The Lancet Infectious Diseases: Experts warn of a surge in vector-borne diseases as humanitarian crisis in Venezuela worsens
The ongoing humanitarian crisis in Venezuela is accelerating the re-emergence of vector-borne diseases such as malaria, Chagas disease, dengue, and Zika virus, and threatens to jeopardize public health gains in the country over the past two decades, warn leading public health experts.

Glow-in-the-dark paper as a rapid test for infectious diseases
Researchers from Eindhoven University of Technology (The Netherlands) and Keio University (Japan) present a practicable and reliable way to test for infectious diseases.

Math shows how human behavior spreads infectious diseases
Mathematics can help public health workers better understand and influence human behaviors that lead to the spread of infectious disease, according to a study from the University of Waterloo.

Many Americans say infectious and emerging diseases in other countries will threaten the US
An overwhelming majority of Americans (95%) think infectious and emerging diseases facing other countries will pose a 'major' or 'minor' threat to the U.S. in the next few years, but more than half (61%) say they are confident the federal government can prevent a major infectious disease outbreak in the US, according to a new national public opinion survey commissioned by Research!America and the American Society for Microbiology.

Read More: Infectious Diseases News and Infectious Diseases Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.