Hybrid particle mimics AIDS virus.

Hybrid particle mimics AIDS virus 

By exploiting peripatetic pieces of yeast's genetic material called retrotransposons, British scientists are hoping to hasten the development of effective AIDS vaccines. "Transposable elements'--DNA segments that readily move from one location on a chromosome to another--were first discovered in maize more than 30 years ago, and later in fruit flies and bacteria. When researchers found several years ago that these restless chunks of DNA can transfer traits like antibiotic resistance between bacteria, they began using them as carriers of foreign DNA in genetic experiments (SN: 10/23/82, p.260).

Scientists at the Oxford-based British Bio-technology Ltd., the University of Oxford and the University of Kent in Canterbury used similar technology in their experiments with yeast retrotransposons, reported in the Spet. 3 NATURE. The retrotransposons code for a group of yeast proteins that assemble themselves into harmless "virus-like particles'--which the researchers have tricked into accepting segments from the HIV viruses causing AIDS.

These hybrid faux-virus particles may be useful in developing both AIDS vaccines and diagnostic tests to detect the HIV viruses, say the scientists. Oxford's Susan M. Kingsman told SCIENCE NEWS that 100 copies of the HIV segments can be incorporated into each "ball of protein' that forms the custom-made particles. The presence of so many repeated units of HIV antigen is likely to elicit better immunity when injected into an animal, she says. Yet-unpublished work by the British researchers suggests that a wide range of proteins, including those from viruses other than HIV, could be inserted into the retrotransposons, says Kingsman.

Noting that the hybrid particles are simple to construct and then purify, the authors also report that rabbits injected with the recombinant particles develop antibodies against the HIV component of the particles, suggesting a "new approach to vaccine production.'