Maturation of the Maternofoetal Transport System for Human γ-Globulin in the Mouse

Abstract

THE plasma concentration of γ globulin (IgG) in the human conceptus after 22 weeks or less of gestation is a fifth to a twentieth of that in the mother^1,2, but from 26 weeks to the end of gestation the two concentrations are the same^1,2. Because the foetus, even at term, can synthesize only small amounts of γG, this marked increase in the plasma IgG seems to be a consequence of an abrupt change in the permeability of the maternofoetal barrier to IgG. We have investigated the nature of this change in permeability in the pregnant mouse.