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This Article Full Text Full Text (PDF) All Versions of this Article: 73/2/280    most recent biolreprod.104.037986v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Le Discorde, M. Articles by Carosella, E. D. Search for Related Content PubMed PubMed Citation Articles by Le Discorde, M. Articles by Carosella, E. D. Agricola Articles by Le Discorde, M. Articles by Carosella, E. D.

HLA-G*0105N Null Allele Encodes Functional HLA-G Isoforms¹

Service de Recherches en Hémato-Immunologie, CEA-DSV-DRM, Institut d'Hématologie, Hôpital Saint-Louis, Paris 75010, France

Expression of the nonclassical HLA class I antigen, HLA-G, is associated with immune tolerance in view of its role in maintaining the fetus in utero, allowing tumor escape, and favoring graft acceptance. Expressed on invasive trophoblast cells, HLA-G molecules bind inhibitory receptors on maternal T lymphocytes and NK cells, thereby blocking their cytolytic activities and protecting the fetus from maternal immune system attack. The HLA-G gene consists of 15 alleles, including a null allele, HLA-G*0105N. HLA-G*0105N presents a single base deletion, preventing translation of both membrane-bound (HLA-G1) and full-length soluble isoforms (HLA-G5) as well as of the spliced HLA-G4 isoform. The identification of healthy subjects homozygous for this HLA-G null allele suggests that the HLA-G*0105N allele may generate other HLA-G isoforms, such as membrane-bound HLA-G2 and -G3 and the soluble HLA-G6 and -G7 proteins, which may substitute for HLA-G1 and -G5, thus assuming the immune tolerogeneic function of HLA-G. To investigate this point, we cloned genomic HLA-G*0105N DNA and transfected it into an HLA-class I-positive human cell line. The results obtained indicated that HLA-G proteins were indeed present in HLA-G*0105N-transfected cells and were able to protect against NK cell lysis. These findings emphasize the role of the other HLA-G isoforms as immune tolerogeneic molecules that may also contribute to maternal tolerance of the semiallogenic fetus as well as tumor escape and other types of allogeneic tissue acceptance.

embryo, gene regulation, immunology, implantation, pregnancy

² Correspondence: Magali Le Discorde, Service de Recherches en Hé mato-Immunologie, CEA-DSV-DRM, Institut d'Hématologie, Hôpital Saint-Louis, Paris 75010, France. FAX: 33 1 48 03 19 60; teyssier{at}dsvidf.cea.fr