Featured Research

from universities, journals, and other organizations

Key to universal flu vaccine: Embrace the unfamiliar

Date:
August 25, 2014
Source:
Emory Health Sciences
Summary:
Human volunteers immunized against the avian flu virus H5N1 readily developed antibodies against the stem region of the viral hemagglutinin protein. In contrast, those immunized with standard seasonal trivalent vaccines did not, instead developing most of their antibodies against the more variable head region.

Vaccine researchers have developed a strategy aimed at generating broadly cross-reactive antibodies against the influenza virus: embrace the unfamiliar.

Related Articles


In recent years, researchers interested in a "universal flu vaccine" identified a region of the viral hemagglutinin protein called the stem or stalk, which doesn't mutate and change as much as other regions and could be the basis for a vaccine that is protective against a variety of flu strains.

In an Emory Vaccine Center study, human volunteers immunized against the avian flu virus H5N1 readily developed antibodies against the stem region of the viral hemagglutinin protein. In contrast, those immunized with standard seasonal trivalent vaccines did not, instead developing most of their antibodies against the more variable head region. H5N1, regarded as a potential pandemic strain, is not currently circulating in the United States and the volunteers had not been exposed to it before.

The results are scheduled for publication in Proceedings of the National Academy of Sciences.

The key to having volunteers' bodies produce antibodies against the stem region seemed to be their immune systems' unfamiliarity with the H5N1 type of virus, says lead author Ali Ellebedy, PhD, postdoctoral fellow in the laboratory of Rafi Ahmed, PhD, director of Emory Vaccine Center.

Collaborators at University of Chicago and Mount Sinai School of Medicine contributed to the study.

"Our previous research led us to hypothesize that immune responses to the stem region are likely to be stronger after exposure to hemagglutinin molecules derived from flu viruses which the human population has been minimally exposed to," Ellebedy says.

Emory Vaccine Center researchers had found that several patients infected with the 2009 H1N1 pandemic flu strain developed broadly cross-reactive antiviral antibodies. In 2009, most younger adults had never been exposed to the H1N1 pandemic strain and thus had no immune cells producing antibodies against it.

But later, after that H1N1 strain started circulating widely in the population, it became part of the standard seasonal trivalent vaccine. When volunteers' immune responses to the seasonal vaccine were analyzed, most of the antibodies they generated reacted to the head region of hemagglutinin.

Immune cells that produce antibodies against the stem region are widely prevalent in humans, but at low levels, the team found. But the standard trivalent seasonal vaccine tends not to amplify them. This led the team to ask whether vaccination with something different enough, such as H5N1, would stimulate production of "anti-stem" antibodies.

"We had already performed a big H5N1 study back in 2008, so we went back and tested our hypothesis with some novel reagents that allowed us to dissect responses that are directed to the head vs. the stem regions," Ellebedy says.

The team analyzed levels of antibody directed against different parts of the hemagglutinin protein in 17 volunteers, before and after H5N1 vaccination. Anti-stem antibody levels rose an average of four-fold after the first H5N1 vaccination. After a booster shot, however, anti-head responses dominated while anti-stem responses were feeble.

The authors conclude:

"Our data indicate that most humans are capable of establishing a humoral immune memory that is specific to the conserved HA stem region…Overall, our data raise the important question of what would be the minimal 'concentration' of antistem antibodies required to provide in vivo protection. Therefore, it will be important in future studies to determine the quantity of HA stem-specific antibodies or memory B cells that would positively correlate with better clinical outcomes against influenza infections."

"Our findings delineate a potential vaccination strategy where H5N1 or H7N9 immunization could be used not only for immunologically priming the population to quickly respond to serious pandemic influenza threats, but also for generating broadly neutralizing antibodies against influenza in humans."


Story Source:

The above story is based on materials provided by Emory Health Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ali H. Ellebedy, Florian Krammer, Gui-Mei Li, Matthew S. Miller, Christopher Chiu, Jens Wrammert, Cathy Y. Chang, Carl W. Davis, Megan Mccausland, Rivka Elbein, Srilatha Edupuganti, Paul Spearman, Sarah F. Andrews, Patrick C. Wilson, Adolfo Garcνa-Sastre, Mark J. Mulligan, Aneesh K. Mehta, Peter Palese, and Rafi Ahmed. Induction of broadly cross-reactive antibody responses to the influenza HA stem region following H5N1 vaccination in humans. PNAS, August 2014 DOI: 10.1073/pnas.1414070111

Cite This Page:

Emory Health Sciences. "Key to universal flu vaccine: Embrace the unfamiliar." ScienceDaily. ScienceDaily, 25 August 2014. <www.sciencedaily.com/releases/2014/08/140825152554.htm>.
Emory Health Sciences. (2014, August 25). Key to universal flu vaccine: Embrace the unfamiliar. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2014/08/140825152554.htm
Emory Health Sciences. "Key to universal flu vaccine: Embrace the unfamiliar." ScienceDaily. www.sciencedaily.com/releases/2014/08/140825152554.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Feast Your Eyes: Lamb Chop Sent Into Space from UK

Feast Your Eyes: Lamb Chop Sent Into Space from UK

Reuters - Light News Video Online (Nov. 25, 2014) — Take a stab at this -- stunt video shows a lamb chop's journey from an east London restaurant over 30 kilometers into space. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Cambodian Capital's Only Working Elephant to Retire in Jungle

Cambodian Capital's Only Working Elephant to Retire in Jungle

AFP (Nov. 25, 2014) — Phnom Penh's only working elephant was blessed by a crowd of chanting Buddhist monks Tuesday as she prepared for a life of comfortable jungle retirement after three decades of giving rides to tourists. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Buzz60 (Nov. 24, 2014) — A Swedish Adventure racing team travels to try and win a world title, but comes home with something way better: a stray dog that joined the team for much of the grueling 430-mile race. Jen Markham has the story. Video provided by Buzz60
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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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