title: Letter: The placenta as an immunological barrier.
mesh_terms: D005260:Female; D006023:Glycoproteins / Q000276:immunology; D006084:Graft Rejection; D006801:Humans; D008213:Lymphocyte Activation; D010920:Placenta / Q000276:immunology*; D011247:Pregnancy
chemical_list: D006023:Glycoproteins