Immunofluorescent Examination of the Human Chorionic Villus for Blood Group a and B Substance

Abstract

The placenta is a homograft of unusual tenure. Several theories have been proposed in an attempt to explain this apparent homograft immunity. Basic to this problem is the question of trophoblastic antigenicity. One facet of this question is the transportation of trophoblast into the maternal circulation in normal gestations. Since these cells are of fetal origin the possibility of ABO isoimmunization occurring secondary to their transportation is evident. Such an immunologic response might also contribute to the rapid destruction of these cells by the maternal host.Of equal interest is a large body of statistical evidence which points to the selective intrauterine loss of gestations associated with fetal-maternal incompatibility within the ABO system. These questions have led us to study human placentas of various gestational ages for the presence of blood group substances by means of [mmunofluorescent (IF) staining. This paper presents the first phase of this work, the search for A and B substance in the trophoblast of the human term placenta. Materials and MakodsTissue.--AU tissue specimens were obtained at the time of delivery or surgical removal and were quick-frozen in egg albumin mounts in a dry ice-acetone mixture at --40°C as described by Rahman and Luttrell (1). These specimens include representative areas of term placentas, blocks of adult myometrium, cervix, stomach, and fetal kidney. These tissue blocks were stored at --20°C until sectioning in a eryostat immediately prior to incubation with the antis e r u m .

Transplacental passage of blood cells.

“…What is still unanswered is why these cells so seldom cause an immune reponse. Actually, it is even more surprising that trophoblasts-fetal The explanation was advanced that trophoblastic villi are deficient in blood group antigens, and this has been verified (Thiede et al, 1965;Gross, 1966). After enzyme digestion, however, transplantation antigens have been possible to demonstrate in trophoblasts (Currie et al, 1968), so the 'absence' of antigens is probably a consequence of suppression by the mucoprotein layer coating these cells.…”

Immunohistochemical localization of chorionic gonadotrophin on baboon placenta, dispersed trophoblast cells and those derived from blastocysts grown in vitro

“…Histochemical and immunofluorescent techniques coupled with lightor electron-microscopy have shown that hCG is localized predominantly in the human syncytiotrophoblast (Beck et ai, 1969;Hamanaka et ai, 1971;Genabacev et ai, 1972;Genabacev & Sulovic, 1975). However, other workers have shown that human CG can be localized on the cytotrophoblast (Thiede & Choate, 1963;Loke et ai, 1972;Tojo et ai, 1974) and these results have been mostly obtained in studies utilizing human trophoblast cultured in vitro. The baboon produces a CG similar to hCG during pregnancy (Bambra, 1987) and the studies reported herein were carried out to determine its cellular origin on fixed placental sections, placental trophoblast cells cultured in vitro and trophoblast derived from embryos grown in vitro.…”

Pregnancy Rejection Induced by Neuraminidase-Treated Placental Cells

“…However, there is no agreement on the nature of this immunological barrier; according to some workers it is set up by the trophoblastic layer [12,17], while others think that non-cellular components of the placenta carry out this function [13,[18][19][20]; and still others suggest that enhancement may play a role during pregnancy [21,22], Morphological studies showing that trophoblastic and fibrinoid layers are both discontinuous make it hard to believe that they can perform a complete separation between mother and fetus [23,24]. However, anatomical discon tinuity does not necessarily mean functional discontinuity since fetal trans plantation antigens passing through the placenta could be quantitatively in sufficient to elicit homograft immunity into the mother.…”