Making viruses pass for 'safe'

Mar 08, 2011

Viruses can penetrate every part of the body, making them potentially good tools for gene therapy or drug delivery. But with our immune system primed to seek and destroy these foreign invaders, delivering therapies with viruses is currently inefficient and can pose a significant danger to patients.

Now scientists at the University of Pennsylvania have engineered a virus with potential to solve this problem. They describe the new virus today at the 55th Annual Biophysical Society Meeting in Baltimore, MD.

"We would like to find a way to avoid the immune system and maximize the dose delivered to a tumor or diseased tissue," explains professor Dennis Discher of the University of Pennsylvania. He and his colleagues have created a lentiviral vector that expresses CD47, the "marker of self" protein, on its surface. The protein gives cells a free license from macrophages, the immune system's policemen.

"This marker of self protein is found on all of our cells and tames our ," says Discher, senior study author. Discher explains that every cell is like a driver. A macrophage 'policeman' pulls each cell over at a traffic stop and checks its drivers license -- the marker protein. "The policeman says go on if it's valid. If not, then the macrophage eats you," he says.

By tagging CD47 with , the team confirmed that the engineered virus, which is hundreds of times smaller than human cells, was carrying the marker of self. "Assessing the expression of the protein on the surface of an individual virus has been a real biophysical challenge, addressed with a combination of single molecule fluorescence methods and atomic force microscopy," says lead author Nisha Sosale, a graduate student at the University of Pennsylvania.

In cell culture experiments in the laboratory, the engineered virus passed inspection and was eaten less frequently by . "It looks like, by engineering the viral surface, we have made the viruses look like self," says Discher.

Explore further: New compounds protect nervous system from the structural damage of MS

More information: The presentation, "Reducing Immune Response Against Lentiviral Vectors: Lentiviral Vector Presentation of CD47, the 'Marker of Self'" by Nisha Sosale, Richard K. Tsai, Irena Ivanovska, and Dennis E. Discher is at 1:45 p.m. on Tuesday, March 8, 2011 in the Baltimore Convention Center, Hall C. ABSTRACT: tinyurl.com/4wc4o2q

Provided by American Institute of Physics

not rated yet
add to favorites email to friend print save as pdf

Related Stories

Policing cells demand ID to tell friend from foe

Mar 11, 2008

University of Pennsylvania scientists studying macrophages, the biological cells that spring from white blood cells to eat and destroy foreign or dying cells, have discovered how these “policemen” differentiate between ...

Penn researchers discover new mechanism for viral replication

Aug 16, 2007

Researchers at the University of Pennsylvania School of Medicine have identified a new strategy that Kaposi’s Sarcoma Associated Herpesvirus (KSHV) uses to dupe infected cells into replicating its viral genome. This allows ...

Many cancer cells found to have an 'eat me' signal

Dec 22, 2010

Researchers at the Stanford University School of Medicine have discovered that many cancer cells carry the seeds of their own destruction — a protein on the cell surface that signals circulating immune cells to engulf ...

How HIV hides itself

Apr 01, 2008

Researchers have discovered how Human Immunodeficiency Virus (HIV), which causes AIDS, can hide itself in our cells and dodge the attention of our normal defences, scientists heard today at the Society for General Microbiology’s ...

Recommended for you

Mystery of the reverse-wired eyeball solved

18 hours ago

From a practical standpoint, the wiring of the human eye - a product of our evolutionary baggage - doesn't make a lot of sense. In vertebrates, photoreceptors are located behind the neurons in the back of the eye - resulting ...

Neurons controlling appetite made from skin cells

18 hours ago

Researchers have for the first time successfully converted adult human skin cells into neurons of the type that regulate appetite, providing a patient-specific model for studying the neurophysiology of weight ...

Quality control for adult stem cell treatment

21 hours ago

A team of European researchers has devised a strategy to ensure that adult epidermal stem cells are safe before they are used as treatments for patients. The approach involves a clonal strategy where stem cells are collected ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

PPihkala
not rated yet Mar 08, 2011
Let's hope that no harmful virus does obtain this shield. Then their eradication would be much harder, with this 'invisibility cloak' on.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.