[CIRP Note: Lysosyme is also found in subpreputial moisture.]
In a study published today in the Proceedings of the National Academy of Sciences, scientists found that a protein called lysozyme was able to kill the AIDS virus quickly in test-tube experiments.
Sylvia Lee-Huang of New York University, lead researcher in the study, said the protein could become an important drug against HIV because it is a natural compound that the body routinely makes in tears and saliva.
"It ought to be more tolerated and have fewer side effects than other HIV drugs," said Lee-Huang. "It possibly could be used in combination with other drugs."
It's not known how lysozyme kills HIV, but Lee-Huang speculated that it could work by breaking down the outer membrane of the virus.
The team also found that the urine of pregnant women contains another type of protein, called ribonucleases, that destroys the genetic material in the HIV virus.
Nava Sarver, an AIDS researcher at the National Institute of Allergy and Infectious Diseases, said the study was interesting but needs to be confirmed by other laboratories.
"A lot of work needs to be done to simulate the (laboratory) findings in a more relevant situation," said Sarver. Her agency, NIAID, is part of the National Institutes of Health.
The search for the anti-HIV protein was prompted, said Lee-Huang, when researchers realized the babies of women infected with HIV were somewhat protected from the virus.
Researchers earlier suspected that human chorionic gonadotropin, or HCG, a hormone produced during pregnancy, was responsible for protecting against HIV and other viruses.
Lee-Huang said she and her group purified HCG and found it had no effect on HIV. The researchers then spent two years isolating other proteins in urine and testing them against HIV. Eventually they found lysozyme and ribonucleases.
The researcher speculated that pregnancy prompts a woman's body to make more virus-killing proteins to protect the developing baby from viruses and bacteria. That suggests "Mother Nature knows best how to protect the earliest stages of life," Lee-Huang said.
The proteins also were found in mother's milk, white blood cells and chicken egg whites.
The presence of lysozyme in saliva may be a factor in why HIV is not transmitted by casual kissing, said Lee-Huang.
The team is trying to determine exactly how lysozyme attacks HIV. That is a critical step in developing a new HIV drug based on the protein, she said.