MAR 14, 2016 02:52 PM PDT

Defining the Role of Tumor Necrosis Factor During Chronic Viral Infections

WRITTEN BY: Kara Marker
Some viral infections, like HIV, are chronic, while others are acute. HIV infections are labeled chronic because the virus targets and kills helper T cells, and without these lymphocytes the body cannot fight off the HIV infection. Viruses causing acute infections, like the seasonal “stomach bug,” work differently and can be eliminated by the body.

New research from a collaboration between the University of Bonn, University of Cologne, and the Technical University of Munich has led to the discovery of an explanation for why certain viral infections are chronic and others are not. This same discovery has promise for generating new therapeutic targets.
 
Helper T cells secrete inflammatory messengers, a kind of “distress call” to killer T cells to come to their aid and fight off invading pathogens. However, viruses that cause a chronic infection, like HIV, employ virulence factors to silence these messages, ironically rendering the helper T cells helpless and ineffective.
 
In the recent collaborative study, published in the journal Nature Immunology, scientists studied mice models of chronic viral infection to see which helper T cell genes remain active when silenced by viruses. They were able to implicate tumor necrosis factor (TNF) as an agent of chronic viral infection. TNF controls various signaling pathways that inhibit helper T cell activity during chronic inflammation. In mice suffering from HIV-esque chronic viral infections with TNF inactivated, helper T cells produce inflammatory messengers like normal.
 
TNF plays a role in several different functions.

 
“After ten days, the animals had completely eliminated the virus; they were healthy,” explained Dr. Marc Beyer from the University of Bonn.
 
Meanwhile, during acute viral infections, TNF has the opposite effect. It boosts the immune system and stimulates apoptosis in cells corrupted by viral particles.
 
“In an acute infection, large quantities of TNF are formed very rapidly," said Dr. Zeinab Abdullah from the University of Bonn. "In chronic infections, on the other hand, the body secretes small amounts of TNF over a long period of time. This appears to cause the helper T cells to shut down to some extent."
 
The difference seems to stem from some sort of protective mechanism that prevents healthy tissues from being damaged from persistent inflammation, however the team is still in the dark about how exactly TNF works on a molecular level. For the time being, TNF inhibitors could be useful as a therapeutic treatment for patients with chronic viral infections like they are currently used for patients with rheumatoid arthritis and other autoimmune diseases.
 
 
Source: University of Bonn
 
About the Author
  • I am a scientific journalist and enthusiast, especially in the realm of biomedicine. I am passionate about conveying the truth in scientific phenomena and subsequently improving health and public awareness. Sometimes scientific research needs a translator to effectively communicate the scientific jargon present in significant findings. I plan to be that translating communicator, and I hope to decrease the spread of misrepresented scientific phenomena! Check out my science blog: ScienceKara.com.
You May Also Like
APR 28, 2018
Cardiology
APR 28, 2018
Eating Dark Chocolate Reduces Stress, Improves Mood
We’ve heard that dark chocolate is good for us in reasonable amounts, but two unique studies from the Loma Linda University Adventist Health Sciences...
MAY 16, 2018
Immunology
MAY 16, 2018
Antibodies Neutralize Two Different Hemorrhagic Fever Viruses
Scientists have found evidence for potential antibody-based therapeutics to treat more than one hemorrhagic fever virus at once. From Harvard Medical Schoo...
JUN 02, 2018
Immunology
JUN 02, 2018
New Test Predicts Lupus Onset
Based on several different factors, scientists have a new risk index for predicting who will develop lupus. From the Feinstein Institute for Medical Resear...
SEP 05, 2018
Immunology
SEP 05, 2018
B Cells Contribute to Brain Lesions in Multiple Sclerosis
B cells lead to T cell activation resulting in damage to the myelin sheath and brain cells in multiple sclerosis pathogenesis....
SEP 07, 2018
Health & Medicine
SEP 07, 2018
What's Behind the Massive Measles Outbreak in Europe?
Measles is a disease that many believe was eradicated years ago. That's true, to a point, but like a bad penny, it's back. In the United States, th...
SEP 11, 2018
Cannabis Sciences
SEP 11, 2018
The Potential Anti-cancer Effects of Cannabinoids
They're known for helping to reduce the impact of cancer drug side effects, but it's possible that cannabinoids themselves are cancer fighters....
Loading Comments...