IU Researchers Identify Viral Proteins That Evade Human Immune System

INDIANAPOLIS -- Researchers at Indiana University School of Medicine have identified a novel viral mechanism which could result in a new method for treating auto-immune conditions such as asthma and rheumatoid arthritis.

The report on the discovery is detailed in the Sept. 2 issue of the Proceedings of the National Academy of Sciences.

The researchers have identified a viral protein that blocks cells from the human immune system, preventing white blood cells and other inflammatory cells from reaching the site of an infection.

The viral mechanism which evades the host immune system resembles human chemokines, which are small proteins that recruit inflammatory cells to the site of infection to begin the healing process. These are the first viral chemokine-like proteins shown to antagonize the cell-attracting activity of human chemokines.

The "decoy" protein was identified when recent sequencing of the genome of molluscum contagiosum virus type 1, a poxvirus that causes contagious skin infections in humans, revealed a viral protein that closely resembled a human chemokine (macrophage inflammatory protein). Not only does this decoy protein fail to attract inflammatory cells to the site of the infection, but it inhibits other human chemokines from attracting additional inflammatory cells to the site. Similar proteins were identified in two different types of molluscum contagiosum virus.

"We don't know if this is unique to this virus or not, but there are (at least) three other viruses that have chemokine-like proteins," said senior author, Kenneth H. Fife, M.D., Ph.D.

This research emphasizes the variety of ways viruses have developed to escape the host immune system, Fife said.

Additional research is necessary, but Fife said it is possible that viral proteins could be used therapeutically to block inflammation in other conditions where chemokines play a role, such as asthma, rheumatoid arthritis and other auto-immune illnesses.

The molluscum contagiousum virus is not life-threatening, but produces annoying skin lesions and is frequently seen in children. The virus can produce large, disfiguring lesions in AIDS patients. Both types of the virus studied cause disease in humans.

In addition to Fife, who is in the IUSM Department of Medicine, Division of Infectious Disease, and the Department of Microbiology and Immunology, IUSM authors include Mitchell D. Krathwohl, M.D., a fellow in the Division of Infectious Disease; Robert Hromas, M.D., associate professor of medicine, biochemistry and molecular biology and a principal investigator with the Walther Oncology Center; Darron R. Brown, M.D., associate professor of medicine, microbiology and immunology, and Hal E. Broxmeyer, Ph.D., professor of microbiology and immunology and scientific director of the Walther Oncology Center.

Send to: I.U. School of Medicine
Office of Public & Media Relations

INDIANA UNIVERSITY
SCHOOL OF MEDICINE

MEDIA
RELATIONS

A STATEWIDE
RESOURCE

Phone
317 274 7722

Fax
317 278 8722