Víc než jenom jídlo!
Graphic from "Evolution of the mammary gland from the innate immune system?" by Vorbach, Capecchi and Penninger, 2006.
http://capecchi.genetics.utah.edu/PDFs/150Vorbach.pdf
Via Lakeshore Medical Breastfeeding Clinic:
"What if the mammary gland was not initially meant to provide nutrition but developed, at first, to be part of the innate immune system? The innate immune system is a rapid, generalized defense system and is run by small peptides and T-cells. The innate immune system is different from the acquired immune system, which is predominantly immunoglobulins and is very specific.
In embryology, skin glands with protective infection-fighting effects are very common. The mammary gland evolved from a mucus-secreting skin gland, which would then help protect the skin of the newborn, even if the "newborn" was an egg. Mucous secretion contains many things we've already talked about: lactoferrin, IgA and others I haven't posted about yet like xanthine oxidoreductase (XOR) and lysozyme. Those same protective skin mucus secretions are also found in the mammary cells.
XOR, as well as being an important part of the innate immune system is also crucial in milk fat droplet secretion. Lysozyme is an anti-microbial but also evolved into alpha -lactalbumin, a nutritional whey protein special to the lactating breast. So both have two roles- one protective, one nutritional. For both though, their immune system function came first.
So, the mammary gland went from an immune system gland to a protective and nutritional gland --one that is unique to mammals. Breastmilk is more than just food."
