title: The immunomodulatory proteins B7-DC, B7-H2, and B7-H3 are differentially expressed across gestation in the human placenta.
abstract: Placental trophoblast cells form a cellular barrier between the potentially immunogenic fetus and maternal leukocytes. Trophoblasts subvert maternal immunity by producing surface-bound and soluble factors that interact with maternal leukocytes. Here, we describe the distribution of three members of the expanding family of B7 immunomodulatory molecules: B7-DC, B7-H2, and B7-H3. B7-DC and B7-H3 inhibit antigen-stimulated lymphocyte activation while B7-H2 serves in a regulatory capacity, often promoting a Th2 immunophenotype. First trimester and term placentas, purified trophoblast cells, choriocarcinoma cell lines, and human umbilical vein endothelial cells were analyzed for B7 family RNA and protein expression. Transcripts and proteins for all three B7s were present throughout gestation but were differentially expressed within the trophoblast and the stroma. Whereas B7-DC was prominent on the syncytiotrophoblast of early placenta, it was absent from the trophoblast at term. In contrast, B7-H2 and B7-H3 were prominent on the extravillous trophoblast throughout gestation. Lastly, stromal cells, including macrophages and endothelial cells, differentially expressed B7-DC, B7-H2, and B7-H3, depending on gestational age. Thus, all three of these newly discovered B7 proteins are differentially positioned at the maternal-fetal interface such that they could steer maternal leukocytes away from a harmful immune response and toward a favorable one.
authors.affiliation: Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160-7400, USA. mpetroff@kumc.edu
authors.forename: Margaret G
authors.initials: MG
authors.lastname: Petroff
authors.forename: Elza
authors.initials: E
authors.lastname: Kharatyan
authors.forename: Donald S
authors.initials: DS
authors.lastname: Torry
authors.forename: Lesya
authors.initials: L
authors.lastname: Holets
mesh_terms: D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen / Q000235:genetics / Q000378:metabolism*; D002822:Choriocarcinoma / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D006801:Humans; D007155:Immunologic Factors / Q000378:metabolism*; D060945:Inducible T-Cell Co-Stimulator Ligand; D008213:Lymphocyte Activation; D008264:Macrophages / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000378:metabolism; D061027:Programmed Cell Death 1 Ligand 2 Protein; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017154:Stromal Cells / Q000378:metabolism; D018418:Th2 Cells / Q000378:metabolism; D014327:Trophoblasts / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D060887:B7 Antigens; D018122:B7-1 Antigen; C423237:CD276 protein, human; C498514:ICOSLG protein, human; D007155:Immunologic Factors; D060945:Inducible T-Cell Co-Stimulator Ligand; C556977:PDCD1LG2 protein, human; D061027:Programmed Cell Death 1 Ligand 2 Protein; D011506:Proteins; D012333:RNA, Messenger; D011971:Receptors, Immunologic