Featured Research

from universities, journals, and other organizations

Experimental Vaccine Protects Mice Against Deadly 1918 Flu Virus

Date:
October 24, 2006
Source:
NIH/National Institute of Allergy and Infectious Diseases
Summary:
Federal scientists have developed a vaccine that protects mice against the killer 1918 influenza virus. They also have created a technique for identifying antibodies that neutralize this virus, a tool that could help contain future pandemic flu strains. These findings are important, the researchers say, to understanding and preventing the recurrence of the H1N1 influenza virus that caused the 1918 pandemic and to protecting against virulent flu strains in the future, including the H5N1 avian flu virus.

Federal scientists have developed a vaccine that protects mice against the killer 1918 influenza virus. They also have created a technique for identifying antibodies that neutralize this virus, a tool that could help contain future pandemic flu strains. These findings are important, the researchers say, to understanding and preventing the recurrence of the H1N1 influenza virus that caused the 1918 pandemic and to protecting against virulent flu strains in the future, including the H5N1 avian flu virus. Details of the research are available online this week in Proceedings of the National Academy of Sciences.

Gary J. Nabel, M.D., Ph.D., director of the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), led the research team in developing the experimental vaccines and conducting the immunological studies in mice. Terrence Tumpey, Ph.D., of the Centers for Disease Control and Prevention (CDC) conducted vaccine studies in mice involving the live, reconstructed 1918 flu virus in a biosafety level 3-enhanced laboratory at the CDC in Atlanta--one of four types of specialized biosafety labs where scientists study contagious and potentially deadly materials under high-level safety and contamination precautions designed to protect the researchers and prevent microorganisms from entering the environment.

"Understanding why this influenza virus was so deadly is an extremely important question," says NIAID Director Anthony S. Fauci, M.D. "By building upon earlier research where scientists successfully reconstructed the 1918 pandemic flu strain, Dr. Nabel and his colleagues have demonstrated that this virus is vulnerable to intervention. This knowledge will help further our continued efforts to develop treatments and vaccines to protect us against another deadly flu pandemic."

The 1918-1919 influenza pandemic was the most deadly flu outbreak in modern history, killing 50 million or more people worldwide.

"A key to containing pandemic flu viruses is to understand their vulnerabilities and determine whether they can evade immune recognition," says Dr. Nabel. "What we learn about the H1N1 virus that caused the 1918 pandemic is pertinent to other pandemic viruses and to the development of effective and universal vaccines."

Using the genetic sequence information for the 1918 flu virus, Dr. Nabel and his VRC colleagues created plasmids--small strands of DNA designed to express specific characteristics--carrying genes for the virus' hemagglutinin (HA) protein, the surface protein found in all flu viruses that allows the virus to stick to a cell and cause infection. The researchers created two types of plasmids: one to reflect the HA found in the original 1918 flu virus; the other an altered HA protein designed to attenuate (weaken) the virus.

Mice were then injected with a DNA vaccine containing both types of plasmids to determine whether they would generate immune responses to the 1918 virus. The researchers found significant responses both in terms of production of T-cells, the white blood cells critical in the immune system's battle against invading viruses, as well as the production of neutralizing antibodies.

To determine the vaccine's protective effects, the CDC's Dr. Tumpey intranasally exposed a group of mice to live, reconstructed 1918 virus 14 days after they were immunized with the experimental DNA vaccine. All 10 vaccinated mice survived the challenge with the deadly virus. To explore how the vaccine protected the animals, the researchers first depleted other mice of T-cells; however, this had no effect on the immunity of the vaccinated mice to the 1918 virus. In contrast, the researchers discovered that transferring antibody-rich immunoglobulin (IgG) from immunized mice to non-immunized mice resulted in antibody levels in the animals at levels only slightly lower than those that were immunized. Further, when the animals were exposed to the reconstructed 1918 flu virus, 8 of 10 mice that received antibodies from the immunized mice survived; none of the 10 mice that received IgG from the unvaccinated control group survived.

"By using an existing pandemic flu strain, this research will provide the basis for design of alternative vaccines against influenza viruses with enhanced virulence," says Dr. Tumpey.

Although the researchers are not discounting the potential role T-cells may have in combating flu viruses, they concluded that in this study, the experimental DNA vaccine protected the mice by stimulating antibodies capable of neutralizing the 1918 flu virus.

"Who would have imagined five years ago that we'd be able to create a vaccine that protects against one of the deadliest forms of influenza the world has ever seen?" adds Dr. Nabel. "It's because the 1918 flu virus has been reconstructed that we are now able the further understand it. Hopefully, this virus will help us to develop effective vaccine strategies for current pandemic influenza virus threats."

To evaluate the vaccine's antibody-inducing capabilities while minimizing exposure of lab personnel to the 1918 flu virus, Dr. Nabel and his VRC colleagues also created artificial viruses, or pseudoviruses, featuring the HA of the 1918 flu virus but stripped of the ability to cause infection. The pseudoviruses were then incubated with antibody-containing blood samples from the mice immunized with the DNA vaccine and those that were not. The researchers found that the antibodies from the immunized mice neutralized the pseudoviruses while the blood samples from the mice that were not immunized had no effect. This method was also effective in identifying neutralizing antibodies to the H5N1 avian flu virus and could be used to screen for monoclonal antibodies that may be used as an antiviral treatment, according to Dr. Nabel.

"This technique would be very useful in defining evolving serotypes of flu viruses like H5N1 to develop immune sera and neutralizing monoclonal antibodies that may help to contain pandemic flu," says Dr. Nabel.

The study authors indicate that further testing will be needed to determine whether DNA vaccination can confer immune protection in people similar to that seen in the study mice. Additionally, the use of DNA-based vaccines are being explored as a potential strategy for creating vaccines to protect against the H5N1 avian flu virus.

This research activity is part of a broader effort by the Department of Health and Human Services to accelerate the development and production of new technologies for influenza vaccines within the U.S., including a $1 billion investment earlier this year to support the advanced development of cell-based production technologies for influenza vaccines and will help to modernize and strengthen the nation's influenza vaccine production by creating an alternative to producing influenza vaccines in eggs.

NIAID grantee Adolfo Garcνa-Sastre, Ph.D., of the Mount Sinai School of Medicine in New York, also contributed to the study through his work in reconstructing the virus. In addition to Dr. Nabel, other VRC scientists who contributed to the study include: Wing-Pui Kong, Ph.D.; Chantelle Hood; Zhi-yong Yang; Ling Xu; and Chih-Jen Wei.


Story Source:

The above story is based on materials provided by NIH/National Institute of Allergy and Infectious Diseases. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute of Allergy and Infectious Diseases. "Experimental Vaccine Protects Mice Against Deadly 1918 Flu Virus." ScienceDaily. ScienceDaily, 24 October 2006. <www.sciencedaily.com/releases/2006/10/061017164336.htm>.
NIH/National Institute of Allergy and Infectious Diseases. (2006, October 24). Experimental Vaccine Protects Mice Against Deadly 1918 Flu Virus. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2006/10/061017164336.htm
NIH/National Institute of Allergy and Infectious Diseases. "Experimental Vaccine Protects Mice Against Deadly 1918 Flu Virus." ScienceDaily. www.sciencedaily.com/releases/2006/10/061017164336.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) — The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) — Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins