Ontogeny and distribution of cells expressing HLA-B locus-specific determinants in the placenta and extraplacental membranes.
Both the trophectoderm and the inner cell mass of the blastocyst contribute to the cell populations found in the placenta and extraplacental membranes. Previous studies have shown differences between those two embryologically distinct populations of cells in their expression of class I HLA, and further differences among trophectoderm-derived trophoblast cell subpopulations. Binding patterns for antibodies to both monomorphic and allotypic determinants on class I heavy chains have been reported. In the present study, extraembryonic cells were evaluated by immunohistology for binding of the monoclonal antibody 4E, which identifies locus-specific determinants on HLA-B. Some inner cell mass-derived cells (mesenchymal cells) acquired high levels of HLA-B as gestation progressed and other continued to express low levels at late stages of gestation (amnion cells). In contrast, throughout gestation both villous and extravillous trophoblast cells failed to express detectable HLA-B. The binding patterns for 4E followed the patterns established by a monoclonal antibody to class I HLA heavy chains (61D2), and those reported for antisera to allotypic determinants. The findings support the suggestion that trophoblast cells forming the fetal component of the maternal-fetal interface exert highly effective regulation over the expression of class I HLA.
Hunt
J S
JS
Department of Pathology and Oncology, University of Kansas Medical Center, Kansas City 66103.
Lessin
D L
DL
King
C R
CR
D000911:Antibodies, Monoclonal; D001755:Blastocyst / Q000276:immunology; D005321:Extraembryonic Membranes / Q000276:immunology; D005260:Female; D005865:Gestational Age; D015235:HLA-B Antigens; D006801:Humans; D007150:Immunohistochemistry; D010920:Placenta / Q000276:immunology*; D014327:Trophoblasts / Q000276:immunology
D000911:Antibodies, Monoclonal; D015235:HLA-B Antigens