How Does Breastfeeding Transfer Immunity to Babies?

We've known for years that babies benefit from the antibodies in mom's milk, but the question has always remained...How does immunity get passed along? We now have an answer.

A new study, which will be published in the November issues of the Journal of Immunology, presents evidence by a team of researchers from Brigham Young, Harvard, and Stanford Universities. They have identified a molecule, CCR10, that is critical to a mother's ability to transfer immunity to intestinal infections on to her baby through breast milk. Prior to pregnancy, mom has antibody-producing cells which are circulating throughout her body and reroute to her intestine to protect from infections such as cholera or rotavirus. Once she delivers a baby and begins to lactate, these cells reroute once again to her mammary glands. When the baby breastfeeds, he is receiving those antibodies in his intestinal tract. CCR10 is the key to the whole process as it redirects those cells.

Dr. Eric Wilson, the lead author on the study, states, "Everybody hears that breastfeeding is good for the baby, but why is it good? One of the reasons is that mothers' milk carries protective antibodies which shield the newborn from infection, and this study demonstrates the molecular mechanisms used by the mother's body to get these antibody-producing cells where they need to be."

So what's the next step? Co-author Elizabeth Nielsen Low, an undergraduate student at Brigham Young, believes, "If we know how these cells migrate, we'll be able to hit the right targets to get them to go where we want them."