03/15/99
HIV-Killing Proteins Found in Tears
WASHINGTON (AP)
Tears, saliva and the urine of pregnant women all contain
proteins that are potent killers of HIV, the virus that
causes AIDS, researchers say. The scientists isolated a
protein, called lysozyme, and found that it was able to
kill the AIDS virus quickly in test-tube experiments. A
report on the study appears Tuesday in the Proceedings
of the National Academy of Sciences.
The lysozyme could become an important therapeutic drug
against HIV because it is a natural compound that the
body routinely makes, said Sylvia Lee-Huang, professor
of biochemistry at New York University, who identified
it with colleagues. "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."
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. 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.
Nava Sarver, an AIDS researcher at the National Institute
of Allergy and Infectious Diseases, (part of the National
Institutes of Health) said the study was interesting but
needs to be confirmed by other labs. "A lot of work needs
to be done to simulate the (laboratory) findings in a more
relevant situation," said Sarver.
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
white, and lysozyme was found in saliva and tears. The
presence of lysozyme in saliva may a factor in why HIV is
not transmitted by casual kissing, said Lee-Huang.
The team is now 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.
