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Engineered Virus Delivers 'Suicide Gene Therapy' to HIV-infected Cells

Researchers have developed a lentivirus vector containing the CD4 receptor that can selectively transfer genes only to cells that express HIV envelope proteins, offering the potential for "suicide gene therapy" that targets only infected cells, leaving healthy cells unaffected, researchers reported in the July 23, 2011, issue of Virus Research.

Below is an edited excerpt from a press release issued by the University of Southern California describing this laboratory research.

USC Scientist Develops Virus that Targets HIV

Using a virus to kill a virus

In what represents an important step toward curing HIV, a USC scientist has created a virus that hunts down HIV-infected cells.

Dr. Pin Wang's lentiviral vector latches onto HIV-infected cells, flagging them with what is called "suicide gene therapy" -- allowing drugs to later target and destroy them.

"If you deplete all of the HIV-infected cells, you can at least partially solve the problem," said Wang, chemical engineering professor with the USC Viterbi School of Engineering.

The process is analogous to the military practice of "buddy lasing" -- that is, having a soldier on the ground illuminate a target with a laser to guide a precision bombing strike from an aircraft.

Like a precision bombing raid, the lentiviral vector approach to targeting HIV has the advantage of avoiding collateral damage, keeping cells that are not infected by HIV out of harm's way. Such accuracy has not been achieved by using drugs alone, Wang said.

So far, the lentiviral vector has only been tested in culture dishes and has resulted in the destruction of about 35 percent of existing HIV cells. While that may not sound like a large percentage, if this treatment were to be used in humans, it would likely be repeated several times to maximize effectiveness.

Among the next steps will be to test the procedure in mice. While this is an important breakthrough, it is not yet a cure, Wang said.

"This is an early stage of research, but certainly it is one of the options in that direction," he said.

Wang's research, which was funded by the National Institutes of Health, appears in the July 23 issue of Virus Research.

Investigator affiliations: Mork Family Department of Chemical Engineering and Materials Science, Department of Biomedical Engineering, and Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA.

8/9/11

Reference

C-L Lee, J Dang, K-l Joo, and P Wang. Engineered lentiviral vectors pseudotyped with a CD4 receptor and a fusogenic protein can target cells expressing HIV-1 envelope proteins. Virus Research (abstract). July 23, 2011 (Epub ahead of print).

Other Source

R Perkins, University of Southern California. Scientist Develops Virus that Targets HIV: Using a Virus to Kill a Virus. Press release. August 8, 2011.