The Immune System of Milk
We know that breastfeeding is good for children's health in many ways. Immune factors in milk—including antibodies and other proteins, white blood cells, and even commensal microbes—protect infants against infections and may prevent allergies. Understanding how the "immune system of milk" responds to microbes is critically important to understanding how breastfeeding affects children's health.
The Laboratory for Anthropometry and Biomarkers at Binghamton University (Director, Katherine Wander) has developed a new technique to test how the "immune system of milk" responds to microbes. Our technique "challenges" the immune system of milk with an infectious agent and measures its response. The protocol is simple and low-tech. Milk is diluted in culture medium (which keeps milk cells alive and allows them to respond), an immune stimulant (all or part of an infectious agent, like E. coli) is introduced, and milk is incubated at ~98.6° F for 24 hours. We then measure the concentration of cytokines—mediators of immune responses produced by immune cells—in stimulated and unstimulated milk. We describe milk immune responses to stimuli by comparing cytokine concentrations before and after incubation.
Phase One: The first phase of the project focused on developing and refining the method. ~100 women provided milk specimens. We used these to develop a protocol that allows us to characterize milk immune responses to many gastrointestinal pathogens, including Salmonella, rotavirus, and parasitic worms, and to commensal bacteria, like Lactobacillus.
Cytokines increased dramatically—up to 600 times baseline—in some milk specimens when challenged with gastrointestinal pathogens. Immune responses were apparent in about half of milk specimens. Immune responses were generally much greater for Salmonella than for commensal bacteria.
Pro-inflammatory responses were greater, on average, the older a child was and were greater, on average, for mothers with diagnosed autoimmune disease. See our full publication here.
Phase Two: The second phase of The Immune System of Milk investigates the importance of milk immunity among infants in Kilimanjaro, Tanzania, where gastrointestinal infections are very common and milk immunity is likely to be critical to children's health.
This phase of the project has demonstrated that strong milk immune responses can protect infants against infectious diseases (see our full publication here). It has also challenged the hypothesis that milk immunity strongthens when infants become ill (see our full publication here) and identified patterns in milk immune responses with mothers' age and number of pregnancies (see our full publication here).
More information about the Child Health and Development in Kilimanjaro project can be found here. The LAB and CHDK focus on conducting international health research in remote settings where understanding early childhood nutrition and infectious disease are critical.
Future Directions: In the future, our technique can also be used in research asking questions like:
- Are milk immune responses compromised when mothers are malnourished?
- Do milk immune responses affect infants' autoimmune or allergic disease risk?
This project would not have been possible without our participants, who volunteered their time and donated milk to this project. We are eternally grateful for your patience and your support. We are also grateful to La Leche League of Greater Binghamton and the Southern Tier Breastfeeding Coalition for help in Phase One of this project and to the Kilimanjaro Clinical Research Institute and the Hai District Medical Office for help in Phase Two.
If you are looking for more about the projects findings, please visit the LAB's main page and view the Publications/Posters section.
