Featured Research

from universities, journals, and other organizations

Keeping Herpes Infection In Check: Researchers Describe Immune System Strategies

Date:
October 18, 2008
Source:
University of Pittsburgh Schools of the Health Sciences
Summary:
Herpes simplex virus type I can cause bouts of cold sores, blindness and potentially lethal encephalitis when it reawakens from a quiescent state in the nerve cells it infects. To prevent these consequences, the stealthy virus is kept under constant guard by the immune system, say University of Pittsburgh scientists. Their research challenges the once common notion that latent HSV-1 in sensory neurons is invisible to the immune system.

Herpes simplex virus type I can cause bouts of cold sores, blindness and potentially lethal encephalitis when it reawakens from a quiescent state in the nerve cells it infects.

To prevent these consequences, the stealthy virus is kept under constant guard by the immune system, say University of Pittsburgh scientists. Their research challenges the once common notion that latent HSV-1 in sensory neurons is invisible to the immune system.

Actually, immune cells keep the infection under close surveillance, actively holding HSV-1 in check without destroying the neurons harboring it, said Robert L. Hendricks, Ph.D., Joseph F. Novak professor and vice-chair for research in the Department of Ophthalmology and professor in the Departments of Immunology and Microbiology and Molecular Genetics at the University of Pittsburgh School of Medicine. Sensory neurons may not regenerate, so an immune system attack that destroys them could do more harm than good.

In a paper published in the October 10 issue of Science, teams led by Dr. Hendricks and Paul R. Kinchington, Ph.D., also a professor in the University of Pittsburgh School of Medicine Department of Ophthalmology, show one way this balancing act is carried out.

Immune cells called CD8 T cells attack virus-infected cells with lytic granules, which are packets of potentially toxic enzymes. Transport of lytic granule contents into infected cells typically initiates a process that leads to a form of cellular suicide called apoptosis.

However, according to the researchers' experiments, that isn't the case when CD8 T cells target infected sensory neurons.

"Instead, the lytic granules attack the viral infection in neurons without killing them," explained Dr. Hendricks, senior author. "One way is through a lytic granule enzyme called granzyme B, which cleaves an important HSV-1 protein required for viral replication. That means the neuron and the virus survive, but the infection can't spread to other cells."

Recurrences of cold sores, eye disease and other forms of herpetic lesions occur if the balance shifts and the virus can bypass surveillance by the immune system.

Dr. Hendricks noted that up to 90 percent of people eventually become infected with HSV-1, many in childhood. The initial infection typically produces mild symptoms or none at all, but the virus remains in the neurons for a lifetime, occasionally waking up to cause disease. It repeatedly scars the cornea when this occurs in the eye, making HSV-1 a leading infectious cause of blindness.

Previous studies showed CD8 T cells can use interferon-gamma to block reactivation without killing the neuron, but only some sets of neurons are controlled in this manner, Dr. Hendricks said. His team will continue to try to identify how immune cells, HSV-1 and neurons interact, which could have implications for treatment and vaccine development for HSV-1 infections, as well as for gene therapy applications that use harmless versions of the herpes virus as a vector to ferry treatment genes into cells.

The paper's lead author is Jared E. Knickelbein, Ph.D., and coauthors include Michael B. Yee, B.S., Catherine J. Baty, D.V.M., Ph.D., all of the University of Pittsburgh School of Medicine, and Kamal M. Khanna, Ph.D., University of Connecticut.

The research was supported by the Eye and Ear Foundation of Pittsburgh, New York- based Research to Prevent Blindness and the National Eye Institute.


Story Source:

The above story is based on materials provided by University of Pittsburgh Schools of the Health Sciences. Note: Materials may be edited for content and length.


Cite This Page:

University of Pittsburgh Schools of the Health Sciences. "Keeping Herpes Infection In Check: Researchers Describe Immune System Strategies." ScienceDaily. ScienceDaily, 18 October 2008. <www.sciencedaily.com/releases/2008/10/081009143710.htm>.
University of Pittsburgh Schools of the Health Sciences. (2008, October 18). Keeping Herpes Infection In Check: Researchers Describe Immune System Strategies. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2008/10/081009143710.htm
University of Pittsburgh Schools of the Health Sciences. "Keeping Herpes Infection In Check: Researchers Describe Immune System Strategies." ScienceDaily. www.sciencedaily.com/releases/2008/10/081009143710.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. 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