title: The rhesus monkey analogue of human lymphocyte antigen-G is expressed primarily in villous syncytiotrophoblasts.
abstract: The human placenta expresses the nonclassical major histo-compatibility complex (MHC) class I molecule, human lymphocyte antigen (HLA)-G, which may contribute to the establishment of maternal-fetal immune tolerance. Although the HLA-G ortholog of the rhesus monkey, Mamu-G, is a pseudogene, another nonclassical MHC class I locus, Mamu-AG, is expressed in the rhesus monkey placenta. Mamu-AG encodes MHC class I A locus-related molecules that exhibit all the characteristics of human HLA-G, including limited polymorphism and a truncated cytoplasmic domain. We have examined MHC class I glycoprotein and Mamu-AG mRNA expression in the rhesus placenta and in cultured trophoblasts. Immunocytochemical analysis of rhesus placental tissues with the W6/32 monoclonal antibody demonstrated a high level of MHC class I expression in villous syncytiotrophoblasts, whereas villous cytotrophoblasts were largely MHC class I negative. Only low levels of MHC class I expression were seen in extravillous cytotrophoblasts of cell columns and the trophoblastic shell. In situ hybridization demonstrated that Mamu-AG mRNAs were expressed at a high level in first-trimester villous syncytiotrophoblasts. MHC class I and Mamu-AG expression was significantly up-regulated during in vitro culture and differentiation of freshly isolated villous cytotrophoblasts into syncytiotrophoblasts. Preferential Mamu-AG expression in syncytiotrophoblasts suggests that rhesus monkey MHC class I-bearing trophoblasts could potentially interact with maternal peripheral blood lymphocytes rather than with uterine decidual lymphocytes as has been proposed for human trophoblasts.
authors.affiliation: Wisconsin Regional Primate Research Center, Madison 53715-1299, USA.
authors.forename: I I
authors.initials: II
authors.lastname: Slukvin
authors.forename: J E
authors.initials: JE
authors.lastname: Boyson
authors.forename: D I
authors.initials: DI
authors.lastname: Watkins
authors.forename: T G
authors.initials: TG
authors.lastname: Golos
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015870:Gene Expression; D005805:Genes, MHC Class I; D006680:HLA Antigens / Q000235:genetics / Q000378:metabolism*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008253:Macaca mulatta / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008431:Maternal-Fetal Exchange / Q000276:immunology; D010920:Placenta / Q000276:immunology / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D014327:Trophoblasts / Q000276:immunology* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D012333:RNA, Messenger