Whey, the watery dairy product best known from the tale of Little Miss Muffet, might provide a way to keep the AIDS virus from infecting people during sex.
A modified version of a protein extracted from whey blocked the AIDS virus from infecting cells in the test tube, researchers report.
If tests go well, the modified protein might be put in a cream or foam that could be used with condoms, said researcher A. Robert Neurath.
Neurath is head of the Laboratory of Biochemical Virology at the Lindsley F. Kimball Research Institute of the New York Blood Center. He and colleagues reported the test-tube result in the February issue of Nature Medicine.
An AIDS expert said the work left some key questions unanswered.
Whey is produced when milk is made into cheese. Most of it is then used in other products, including ice cream, bread, pie crust and soups.
For the new work, scientists modified a whey protein called betalactoglobulin to produce a substance they named B69. They found that B69 latched onto a protein structure called CD4 on the surface of cells. That kept the AIDS virus from using CD4 as an entryway into the cells.
In the test tube, B69 blocked infection by free-floating HIV and by HIV traveling in infected cells, Neurath said. Someday, B69 might be put into an over-the-counter product, perhaps in combination with a virus-killing compound, he said.
Dr. Jeffrey Laurence, an AIDS researcher at Cornell Medical College in New York, cautioned that research shows HIV can infect some cells - including cells in the vagina and rectum - without using CD4.
Neurath said preliminary work suggests B69 might block other cell sites that have been proposed as alternative entryways for HIV.
Laurence also said B69 will have to be tested to see if it will harm the tissues it is applied to. Neurath said tests in rabbits and rats suggest side effects are unlikely to be a problem.