Synthetic Tat might be A.I.D.S. cure

Press, 4 September 1989, Page 6

Synthetic Tat might be A.I.D.S. cure

NZPA-KRD Chicago Biologists at two universities have announced that they switched off the trigger mechanism that lets the A.I.D.S. virus reproduce. If the results published in “Cell” are confirmed, the discoveries could lead to effective drug treatments and possibly a cure for A.I.D.S. within a decade, the scientists predicted. Teams of gene splicers at St Louis University School of Medicine and Duke University Medical Centre for the first time used synthetic genes to block the production of proteins that the human immunodeficiency virus, or H.1.V., needs to replicate. The A.I.D.S. virus becomes a living part of patients’ bodies — a formidable obstacle in the battle against it. When infection starts, the virus enters the white blood cells of the immune system and splices its genes into those of the cell, becoming part of the genetic structure. The cell is infected forever. The virus may sleep for

years, but eventually its genes will begin to produce the proteins it needs to make new viruses.

Production of the proteins kills the infected cells, and the new viruses go on to infect other immune cells, killing them in turn until the immune system breaks down, leading to infections that kill the patient. The St Louis study opens the possibility of blocking viral replication in infected people by flooding their bloodstream with bogus viral proteins. The Duke study presents the more distant possibility of curing A.I.D.S. by gene therapy. “These are speculations, but they’re highly encouraging and they’re based on serious science,” said the head of the St Louis team. Dr Maurice Green, chairman of the university’s Institute for Molecular Virology.

Dr Green’s team was able to build a synthetic protein called Tat, almost identical to the Tat protein the A.I.D.S. virus needs to reproduce. The synthetic Tat could turn on latent A.I.D.S.

viruses in cells, showing that it is the key trigger to viral production. When the scientists genetically altered the protein to make it slightly faulty, it jammed the triggering mechanism that normally started the viral reproductive cycle. The scientists were “surprised and delighted” to discover that the protein, when placed outside ceils, was taken up Because the protein is absorbed by cells, Dr Green said, “we probably can put it in the blood system of an individual. Drug delivery should not be a great problem, and we don’t need high levels.” However, another scientist who works with Tat was sceptical. “The results are potentially very exciting,” admitted Dr Alan Frankel, of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts. “But a way to get the proteins into infected cells is still needed. We have not seen the same results as Green and his colleagues.”