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Bio-tech Breakthrough

DW staff / DPA (sac)June 28, 2007

German scientists have succeeded in snipping the virus that causes AIDS out of human cells, leaving them healthy again. The procedure is a breakthrough in bio-technology and fuels hope of a cure for AIDS.

A new enzyme can cut the AIDS virus out of sick cellsImage: AP/Bayer

The laboratory procedure removing the AIDS virus used an enzyme, said Joachim Hauber of the Heinrich Pette Institute for Experimental Virology and Immunology in Hamburg.

"We have rid the cells of the virus," Hauber said on Thursday. "No one else has done this before." He called it "a breakthrough in bio-technology."

Hauber said it was his "cautious" hope that a cure for AIDS could be found within 10 years.

Current therapies can only limit the spread of the human immunodeficiency virus (HIV) and not remove it from the body. HIV is a retrovirus that nests in the DNA or key genetic material of infected cells.

The Max Planck Institute for Molecular Cell Biology and Genetics in Dresden was the partner in the research, which will be reported in Friday's issue of the scientific journal Science.

Cutting DNA and recombining it

Three years of experiments on mice were planned next, to be followed by tests on humans in Hamburg.

DNS Modell, Genetik
The enzyme knows just where to cut the DNAImage: AP

The scientists' method used the ability of so-called recombinase enzymes to cut strands of DNA at certain places like a pair of scissors and recombine the strands.

The new enzyme, Tre, always recognized the right spot to snip the DNA where the HIV started. The scientists said it recognized a characteristic HIV sequence that scarcely ever mutated.

Tre was adapted from an existing natural enzyme, Cre, which recognized similar genetic sequences.

Stem cells necessary for therapy

The laboratories artificially evolved Cre into Tre through more than 120 recombinase generations. Hauber said the cell then flushed out the snipped-away DNA as waste.

AIDS Schleife und Labortests Symbolbild
Scientists have been analyzing the HIV virus for years

"After that, it is healthy," Hauber said.

Any therapy, though, would require stem cells to be obtained from a patient's blood. They would then be treated in the laboratory and re-injected to regenerate a healthy immune system, Hauber said.

"It's high-tech medicine," Hauber said. "You couldn't just take a pill."