A leading AIDS researcher warned in a paper published Friday that certain experiments with the AIDS virus could result in new, more deadly strains of the virus. Although such strains have not been produced, the concern is that they might be.
But other experts said that there is no cause for alarm and that nothing in the paper indicates new strains of the virus that causes acquired immune deficiency syndrome are being formed.
The paper, by Dr. Robert Gallo and his colleagues at the National Cancer Institute, was published in Science magazine.
Gallo reported he grew the AIDS virus in human immune-system cells that had been infected with a mouse leukemia virus, which commonly infects mouse cells.
The AIDS virus reproduced in the immune cells and so did the mouse virus.
Some AIDS virus particles picked up pieces of the mouse virus particles, enabling them to enter cells that would not ordinarily be infected by the AIDS virus alone.
But there was no evidence the AIDS virus particles themselves were
"A note of caution concerning biosafety measures" is suggested, Gallo and his colleagues wrote.
They added that laboratory experiments involving growing AIDS viruses in cells that are infected with mouse viruses could generate "more pathogenic" AIDS viruses.
The researchers also warned that experiments that involve studying the AIDS virus in mice could be misleading because the virus could be altered by coming into contact with mouse viruses.
Science published a commentary saying that although the changes have so far been seen only in cells grown in the laboratory, "the animals might produce viral variants that can spread through novel routes," including "transmission through the air."
Dr. Stephen Goff, a molecular biologist at the College of Physicians and Surgeons at Columbia University in New York, said the experiments did not alarm him.
He said he doubted the virus could change so that it is transmitted through the air, and added that by picking up mouse virus proteins, the AIDS virus will not be more resistant to the things that ordinarily kill it.