German Scientists Snip AIDS Virus Out of Human Cells

In a recent test tube experiment, scientists engineered an enzyme that cut from human cells the DNA for producing HIV, leaving the rest of the DNA intact and HIV-free. Three years of experiments on mice are planned next; if they are successful, human trials could follow.

The lab research used a new recombinase enzyme, Tre, which removed DNA at certain segments and then recombined the remaining strands. Tre was engineered through more than 120 generations from a naturally occurring enzyme, Cre, which recognizes similar genetic sequences, scientists said. After Tre cut HIV-specific genes out of the host's DNA, the cell flushed out the targeted DNA fragment as waste. "After that it is healthy," said Joachim Hauber of Hamburg's Heinrich Pette Institute for Experimental Virology.

"We have rid the cells of the virus. No one else has done this before. It's a breakthrough in biotechnology," said Hauber. The Max Planck Institute for Molecular Cell Biology and Genetics was an equal partner with the Pette Institute in the research.

The procedure offers hope for someday curing AIDS, Hauber said. But any therapy would require stem cells from the patient's blood, treated in the laboratory and re-injected for the immunotherapy, he said. "It's high-tech medicine. You couldn't just take a pill."

The complete report, "HIV-1 Proviral DNA Excision Using an Evolved Recombinase," was published in Science Magazine (2007;316(5833):1912-1915).

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