Glutathione, a natural molecule that is vital to cells in the body, has been found in test-tube experiments to powerfully suppress the spread of the AIDS virus, a researcher reported this week.

Alton Meister, co-author of a study to be published Sunday in the Proceedings of the National Academy of Science, said that two forms of glutathione and one of its constituent amino acids all showed in laboratory tests that they can block up to 90 percent of the spread of the AIDS virus.

"The reduction of virus production was proportional to the amount of {glutathione}," said Meister, chairman of the department of biochemistry at Cornell University Medical College in New York. "It is essentially a straightforward effect. The effect is dose-dependent."

Meister said the experiment does not mean that AIDS is simply the result of a glutathione deficiency or that the compound by itself would control the virus. But he said it is clear that glutathione deficiency may contribute to the spread of AIDS -- and just how the peptide supresses the virus is not known.

Meister and researchers at the National Institutes of Health tested the effects of glutathione against AIDS after researchers noticed that people infected with the virus had very little of the natural peptide.

"People with AIDS seem to have much lower levels," he said. "It could be they are prevented by the virus from making more, or it could be that in an AIDS infection it is being used up."

Meister said that his co-authors at the National Institute of Allergy and Infectious Diseases at the NIH plan to organize a clinical trial in which glutathione-like compounds, in a safe formulation and dosage, would be tested on AIDS patients.

Co-authors in the study were Mary E. Anderson of Cornell University, Thea Kalebic, Audrey Kinter, Guido Poli and Anthony S. Fauci, all of the NIAID.

The aim of the study, said Meister, was to find out if correcting the level of glutathione in the blood would affect the spread of the AIDS virus in the body. Glutathione plays an important, but still unknown, role in the immune system.

To test the concept, the researchers used a nurtured colony of human cells, called the U1 cell line, that has a low level of AIDS viral infection.

"These are human cells that normally produce only a little virus," said Meister. "But you can stimulate the cells, and then they produce a lot more."

The researchers used three types of compounds that stimulated the cells to produce high levels of the human immunodeficiency virus, or HIV, which causes AIDS. Then they added three compounds related to glutathione.

The study was designed to see which of the three compounds worked best. When the researchers checked for the replication of HIV, said Meister, "the amount of virus was greatly cut down" and all three of the compounds worked equally well.

Glutathione, a combination of the amino acids cystine, glutamic acid and glycine, is vital to healthy cell function. In addition to promoting the immune system, the researcher said glutathione also defends cells against metals and excess oxygen. The peptide also helps cell metabolism and protects the health of the cell membrane.