Maternal/fetal interactions: the role of the MHC class I molecule HLA-G.
The unique pattern of class I major histocompatibility complex (MHC) antigen expression seen at the human maternal/fetal interface is thought to be vital for fetal well-being. The lack of polymorphic class I and II MHC antigens on trophoblasts, the only fetal tissue in direct contact with the mother, is likely to be at least a part of the explanation of fetal evasion of allograft rejection. The recent observation that the HLA-G-encoded class I MHC molecule is present on certain subpopulations of cytotrophoblasts suggests that this nonpolymorphic molecule may have a role in the maternal/fetal immune response. Although no experimental evidence exists to support a particular function for HLA-G, reasoned speculation about the possible roles of this nonpolymorphic class I molecule is possible. Data derived from sequence analysis, analysis of HLA-G expression patterns, analysis of the extraembryonic expression patterns of other genes, and analysis of decidual lymphocyte phenotype and function provide insight into the possible functions of HLA-G at the maternal/fetal interface and are considered here.
Schmidt
C M
CM
Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455.
Orr
H T
HT
D001483:Base Sequence; D002823:Chorion / Q000276:immunology; D005314:Embryonic and Fetal Development / Q000276:immunology*; D005260:Female; D006680:HLA Antigens / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology; D008969:Molecular Sequence Data; D010920:Placenta / Q000276:immunology; D011247:Pregnancy
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I