Interleukin 7 from maternal milk crosses the intestinal barrier and modulates T-cell development in offspring

• Published in: PloS one Vol. 6; no. 6; p. e20812
• Main Authors: Aspinall, Richard, Prentice, Andrew M, Ngom, Pa Tamba
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 30-06-2011; Public Library of Science (PLoS)
• Subjects: Animal tissues; Animals; Apoptosis; Biology; Breast feeding; Breast milk; Breastfeeding & lactation; Cell growth; Cell survival; Councils; Cytokines; Female; Fluorescence; Fluorescent indicators; Gastrointestinal Tract - metabolism; Genetic crosses; Hazardous areas; House mouse; Illnesses; Immune response; Immune system; Immunology; Infants; Intelligent design; Interleukin; Interleukin 7; Interleukin-7 - chemistry; Interleukin-7 - metabolism; Interleukin-7 - pharmacology; Interleukins; Intestine; Intestines - metabolism; Laboratories; Lymphocytes; Lymphocytes T; Lymphoid tissue; Male; Medical research; Medicine; Mice; Mice, Inbred C57BL; Mice, Knockout; Milk; Milk - chemistry; Mouse devices; Newborn babies; Nutrition; Offspring; Organs; Pathogens; Pregnancy; Progeny; Rodents; Small intestine; Stem cells; Stomach; Streptococcus infections; Studies; T cells; Thymocytes; Thymocytes - drug effects; Thymus; Gambia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0020812

Breastfeeding protects against illnesses and death in hazardous environments, an effect partly mediated by improved immune function. One hypothesis suggests that factors within milk supplement the inadequate immune response of the offspring, but this has not been able to account for a series of observations showing that factors within maternally derived milk may supplement the development of the immune system through a direct effect on the primary lymphoid organs. In a previous human study we reported evidence suggesting a link between IL-7 in breast milk and the thymic output of infants. Here we report evidence in mice of direct action of maternally-derived IL-7 on T cell development in the offspring.
We have used recombinant IL-7 labelled with a fluorescent dye to trace the movement in live mice of IL-7 from the stomach across the gut and into the lymphoid tissues. To validate the functional ability of maternally derived IL-7 we cross fostered IL-7 knock-out mice onto normal wild type mothers. Subsets of thymocytes and populations of peripheral T cells were significantly higher than those found in knock-out mice receiving milk from IL-7 knock-out mothers.
Our study provides direct evidence that interleukin 7, a factor which is critical in the development of T lymphocytes, when maternally derived can transfer across the intestine of the offspring, increase T cell production in the thymus and support the survival of T cells in the peripheral secondary lymphoid tissue.