Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: thedoc on 31/08/2016 10:53:02

Title: Why do only IgG antibodies cross the placenta into a developing baby?
Post by: thedoc on 31/08/2016 10:53:02

shannon m howell asked the Naked Scientists:
   If IgG antibodies and albumin can cross the cell membrane by pinocytosis, why is this not the case of all antibody therapeutics?
What do you think?

Title: Re: Why do only IgG antibodies cross the placenta into a developing baby?
Post by: chris on 31/08/2016 20:07:10

This is because the trophoblast cells, that make up the placenta, switch on - from about 29 weeks - specific receptors called Fc-gamma. These recognise IgG antibody and move it across the trophoblast layer and into the foetal circulation. But receptors for other classes of immunoglobulin - such as IgM - are not expressed by the trophoblast cells and so there is no mechanism for them to move across and into the baby.