In plain words
Secretory IgA is an antibody the body makes in the gut, the airways, and the breast. The mother makes it in response to germs and foods she has met, and it passes into breast milk. It coats the lining of the baby's gut and airways, where it may help that tissue handle germs. has the highest concentration in the first days after birth. Research suggests milk carries antibodies that reflect the mother's own exposures, including those from her home and work. This is one reason some clinicians describe milk as a living fluid. Secretory IgA is one part of how milk supports the baby. It does not replace vaccines or medical care. Mothers often hear about it in discussions of colostrum, , and the freezer stash.
The deeper version
Secretory immunoglobulin A is a dimeric, J-chain-linked IgA transported across mucosal epithelium by the polymeric immunoglobulin receptor. The secretory component protects it from proteolysis. In the lactating breast, antigen encountered in gut-associated or bronchus-associated lymphoid tissue primes B cells that home to the mammary gland under lactation-related hormonal influence and differentiate into IgA-producing plasma cells, giving milk antibodies specific to maternal exposures (Brandtzaeg, 2010). Colostrum and early milk carry the highest concentrations, and levels decline over the first months of lactation. Concentrations vary between mothers and across the day. Functional effects in infants, including on gut microbiota and respiratory infection, are inferred from observational and mechanistic studies rather than shown in controlled trials.
Where it comes up
- Colostrum and the first days before milk comes inFeeding Your Baby
- Donor milkFeeding Your Baby
- Building and storing a milk stashFeeding Your Baby
- Getting sick while postpartumPostpartum: Your Body
What mothers here say about secretory IgA
No one has posted under this term yet.
Sources
- Brandtzaeg P — The mucosal immune system and its integration with the mammary glands. Journal of Pediatrics 2010