How are Antibodies Transferred to Neonates from the Mother?

So let me think about the functions of mammary gland. Of course, you know that the most important functions in the mammary gland during lactation is to produce milk proteins, such as casein that is important nutrients that should be exactly delivered from the mother to the neonates.

But the thing that I would like to talk to you today in this lecture is not nutrient. I would like to talk to you about how the mothers produce antibody productions that is transferred maternal antibodies which is transferred from the mothers to the babies through breast feeding.

So I think you know that the antibodies can be only produced from B cells. The mammary gland alveoli are not immune tissue basically. So the mammary gland cannot produce antibodies itself. If the mothers need to produce antibodies they should have B cells around the mammary gland. The image is like this, during lactation the mothers recruit the B cells which produce antibodies, and then the B cells produce maternal antibodies. Then the antibodies are transferred to the neonates from the mothers. That is the molecule mechanism by which the maternal antibodies is produced through the breastfeeding.

And in the most mucosal tissues, including mammary gland, digestive organs like small intestines, large intestines, or reproductive tracts, or respiratory tracts the people know that the most important, immunoglobulins which is abundantly produced in this kind of mucosal tissues are IgA. Not IgG or IgM.

For example, if you look at the fecal product and then if you evaluate how much amount of IgA? It’s very high.

In contrast, if you look at the plasma antibodies, that is mostly IgG, then IgM, not IgA Meaning that, the mucosal antibody productions, mostly IgE production is completely different to the systemic antibody productions in plasma. So in our research, we also are interested in looking at the maternal antibody productions. That is IgA productions throughout the productive cycle in the mammary glands.