Scientists have identified a protein in breast milk that neutralizes the AIDS virus and may protect babies from acquiring HIV. Experts say the discovery could lead to a new strategy to shield infants whose mothers are infected with the virus.
Each year, hundreds of thousands of children, born to HIV-positive mothers, become infected with the AIDS virus, during pregnancy or breastfeeding. Anti-retroviral drugs, given to both mothers and their infants, have dramatically reduced that number.
But experts say even without anti-AIDS drugs, only a small percentage of nursing infants becomes infected through breast milk, according to Sallie Permar, a professor of pediatrics and immunology at Duke University in Durham, North Carolina.
“It is actually remarkable that despite the infant being exposed to the virus multiple times daily for up to two years of their life actually only 10 percent of those babies will become infected," said Permar.
That prompted scientists, led by Permar, to try to identify a substance in breast milk that shields the baby from infection.
The team zeroed-in on a protein called Tenacin-C or TNC. The protein is known to be involved in wound healing. But its role in breast milk has been a mystery. But when researchers exposed TNC from breast milk of uninfected women to HIV, the molecule attached itself to the virus and disarmed it.
While antiretroviral drugs are highly effective in limiting mother-to-child transmission of the virus, Permar sees a role for TNC in resource-poor areas where drug treatments for HIV are limited.
“The issues are access to the drugs as well as monitoring. There are issues of toxicity and anti-retroviral drug resistance. And so we think alternative strategies may be needed to completely eliminate infant transmission," she said.
She suggests TNC could be given orally to infants prior to breastfeeding for additional protection against HIV. An article describing how Tenacin-C fights HIV is published in the journal Proceedings of the National Academy of Sciences.