German scientists have succeeded in snipping the virus that causes AIDS out of human cells, leaving them healthy again, they disclosed Thursday in a scientific-journal article. The laboratory procedure, using an enzyme, offers hope of a cure for AIDS, said Joachim Hauber of the Heinrich Pette Institute for Experimental Virology and Immunology in the city of Hamburg, dpa reported. "We have rid the cells of the virus. No one else has done this before. It's a breakthrough in bio-technology," he said. Current therapies can only limit the spread of human immunodeficiency virus (HIV) and not remove it from the body. The Max Planck Institute for Molecular Cell Biology and Genetics in the city of Dresden was the partner in the research, reported in Friday's issue of the journal Science. HIV is a retrovirus that nests in the DNA or key genetic material of infected cells. Hauber said it was his "cautious" hope that a cure for AIDS could be found within 10 years. Three years of experiments on mice were planned next, to be followed by tests on humans in Hamburg. The method uses 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 recognizes the right spot to snip the DNA where the HIV starts. It recognizes a characteristic HIV sequence that scarcely ever mutates, the scientists said. Tre was adapted from an existing natural enzyme, Cre, which recognizes similar genetic sequences. The laboratories artificially evolved Cre into Tre through more than 120 recombinase generations, the scientists said. Hauber said the cell then flushed out the snipped-away DNA as waste. "After that it is healthy," he said. Any therapy would require stem cells to be obtained from a patient's blood, treated in the laboratory and re-injected to regenerate a healthy immune system, he forecast. "It's high-tech medicine. You couldn't just take a pill," he explained.
