Impenetrability of the Mouse Placenta to Maternal Leukaemia Cells

Abstract

THE concept of the placenta as a barrier separating the foetus from the immunological defence mechanisms of the mother^1–3 is in question. There is ample evidence that in humans foetal red cells are present in maternal blood during pregnancy⁴, and if red cells pass from foetus to mother, it is difficult to see why immunologically competent cells do not pass from mother to foetus. Tuffrey, Bishun and Barnes^5,6, using the T6 chromosome marker, concluded that large numbers of maternal cells populate the organs of mice, while Billington et al.⁷, also using the T6 marker, reached the opposite conclusion. Seller⁸, using a somewhat different experimental approach, also found no evidence for the passage of maternal cells into the foetus.