About My Health Careers Internship MedBlogs Contact us
Medindia LOGIN REGISTER
Advertisement

Link Between Immunity and Cells' Starvation Response Revealed

by Bidita Debnath on December 8, 2013 at 10:49 PM
Font : A-A+

 Link Between Immunity and Cells' Starvation Response Revealed

In history, one of the most effective vaccines has been the yellow fever vaccine, which was developed in the 1930s and has been administered to more than 500 million people.

Scientists at Emory Vaccine Center studying immune responses to the yellow fever vaccine have identified a gene whose activation in key immune cells is a sign of a robust response. The gene, called GCN2, encodes a protein involved in sensing amino acid starvation and regulates the process of autophagy, a response to starvation or stress within cells.

Advertisement

The findings highlight a link between antiviral defenses and an ancient way that cells adapt to scarcity, and could help researchers develop vaccines against challenging viruses such as HIV or dengue. The results suggest that vaccine additives (called adjuvants) that are effective in stimulating GCN2 and autophagy would be especially potent in stimulating long-lasting immunity.

The results are scheduled for publication Thursday by the journal Science.

"This is an example of taking a system-wide approach to studying vaccine responses, and how it can reveal new insights about the functioning of the immune system," says senior author Bali Pulendran, PhD. "We were not thinking about the stress response pathway and immunity until our analysis pointed us in that direction."
Advertisement

Pulendran is Charles Howard Candler professor of pathology and laboratory medicine at Emory University School of Medicine and a researcher at Yerkes National Primate Research Center. The co-first authors of the paper are postdoctoral fellows Ravesh Ravindran, PhD and Noor Khan, PhD.

A single dose of the live attenuated viral yellow fever vaccine can protect against disease-causing forms of the virus for decades. Investigators led by Pulendran have been dissecting immune responses to the yellow fever vaccine, taking a genome-wide "systems biology" approach.

They started by looking at all the genes that are turned on a few days after human volunteers were vaccinated against yellow fever and asked: which genes' activations are the signatures of especially strong immune responses later? In particular, Pulendran and his colleagues looked for responses by CD8 "killer" T cells, which are important for eliminating virally-infected cells from the body.

One gene that stuck out was GCN2, because it was induced quickly after vaccination and was a sign that the immune system would later respond with lots of CD8 T cells.

GCN2 was known to be a sensor inside cells that detects low levels of amino acids, the building blocks for proteins. GCN2 regulates the process of autophagy, in which cells respond to starvation or stress by ceasing growth and beginning to digest themselves.

In the Science paper, Pulendran and his colleagues show that GCN2's function is especially critical in dendritic cells, whose job is to "present" information about viruses and other pathogens to the rest of the immune system. Dendritic cells lacking GCN2 are less able to activate CD8 T cells, they found.

Mice that lacked GCN2 had impaired responses to yellow fever vaccine and to inhaled influenza vaccine, the researchers found.

They also found that infection with yellow fever leads to a depletion of amino acids within dendritic cells. When viruses infect dendritic cells, it appears that the viruses start using up the building materials on hand. This tips the dendritic cells into autophagy and raising an alarm with the rest of the immune system, Pulendran says.

"This may have evolved as a mechanism of pathogen sensing that is capable of detecting the footprints of a pathogen, such as depleted amino acids in a local microenvironment," he says.

Source: Eurekalert
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
News Category
What's New on Medindia
Mushroom May Help Cut Down the Odds of Developing Depression
How to Battle Boredom during COVID
Link between Dietary Intake of Plant-based Essential Fatty Acids and Death Risk
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
Immunisation Myasthenia Gravis Blood Group Diet Boils - Treatment by Drugs 

Recommended Reading
Knowledge About HPV Vaccine Effectiveness Lacking: Study
Results presented at the Sixth AACR Conference reveal knowledge about the efficacy of the HPV ......
TB Vaccine may be Useful in Preventing Multiple Sclerosis
A new study reveals that a vaccine used for treating tuberculosis is also effective in preventing .....
GSK's Q-Pan H5N1 Vaccine Receives FDA Nod
The US Food and Drug Administration has finally approved GlaxoSmithKline's Q-Pan H5N1 vaccine for .....
Nanosponge Vaccine Fights MRSA Toxins, Say Researchers
New nanosponge vaccine soaks up a dangerous pore-forming toxin produced by MRSA, say researchers....
Blood Group Diet
What is right diet for you may be the wrong one for another. The diet that suits you will depend on ...
Boils - Treatment by Drugs
Diabetes patients have reduced immunity, which makes them more susceptible to skin infections like b...
Myasthenia Gravis
Myasthenia gravis is the commonest disorder of neuromuscular transmission. Autoimmune myasthenia gra...

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use