June 15, 2012
Can Breastfeeding Prevent HIV?
(Ivanhoe Newswire) — More than 15 percent of new HIV infections occur in children. Without treatment, only 65 percent of HIV-infected children will live until their first birthday, and fewer than half will make it to the age of two. Although breastfeeding is attributed to a significant number of these infections, most breastfed infants are not infected with HIV, despite prolonged and repeated exposure.
This has left researchers wondering if instead of causing HIV, does breastfeeding actually prevent the virus?
New research from the University of North Carolina School Of Medicine explores this paradox in a humanized mouse model, demonstrating that breast milk has a strong virus killing effect and protects against oral transmission of HIV.
Garcia and colleagues pioneered the humanized "BLT" mouse model, which is created by introducing human bone marrow, liver and thymus tissues into animals without an immune system of their own. Humanized BLT mice have a fully functioning human immune system and can be infected with HIV in the same manner as humans.
In the study, the researchers first determined that the oral cavity and upper digestive tract of BLT mice have the same cells that affect oral transmission of HIV in humans and then successfully transmitted the virus to the mice through these pathways. When the mice were given virus in whole breast milk from HIV-negative women, however, the virus could not be transmitted.
Angela Wahl, PhD, a post-doctoral researcher in Garcia's lab and lead author on the paper was quoted as saying, “These results are highly significant because they show that breast milk can completely block oral transmission of both forms of HIV that are found in the breast milk of HIV-infected mothers: virus particles and virus-infected cells.
Dr. Garcia concluded by saying, "No child should ever be infected with HIV because it is breastfed. Breastfeeding provides critical nutrition and protection from other infections, especially where clean water for infant formula is scarce," Garcia said. "Understanding how HIV is transmitted to infants and children despite the protective effects of milk will help us close this important door to the spread of AIDS."
SOURCE: PLoS Pathogens June 2012