Soluble HLA-G in human placentas: synthesis in trophoblasts and interferon-gamma-activated macrophages but not placental fibroblasts

Hum Immunol. 1998 Jul;59(7):435-42. doi: 10.1016/s0198-8859(98)00045-7.


The HLA class Ib antigen, HLA-G, is highly expressed in early gestation placentas where it is believed to modulate maternal-fetal immunological interactions. In this study, soluble isoforms (sHLA-G) encoded by intron 4-retaining transcripts were identified in first trimester placentas by immunohistochemistry using a mAb specific for the C-terminus of sHLA-G. Immunoreactive sHLA-G protein was localized to trophoblast cells and to villous mesenchymal cells with the morphological features of macrophages. Reverse transcriptase polymerase chain reaction analysis which used primers specific for intron 4 and the 3' untranslated region of the HLA-G gene showed that transcripts encoding sHLA-G were present in the trophoblast-derived Jeg-3 cells as well as interferon-gamma-activated myelomonocytic U937 cells but were absent and uninducible in placental fibroblasts. These results indicate that placental sHLA-G is synthesized in trophoblast cells and activated placental macrophages and support the postulate that placenta-derived sHLA-G modulates maternal and fetal immune cell functions during pregnancy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Cell Line
  • Female
  • Fibroblasts / immunology
  • Fibroblasts / metabolism*
  • HLA Antigens / biosynthesis*
  • HLA Antigens / genetics
  • HLA Antigens / immunology
  • HLA-G Antigens
  • Histocompatibility Antigens Class I / biosynthesis*
  • Histocompatibility Antigens Class I / genetics
  • Histocompatibility Antigens Class I / immunology
  • Humans
  • Immunohistochemistry
  • Interferon-gamma / pharmacology*
  • Macrophage Activation*
  • Macrophages / immunology
  • Macrophages / metabolism*
  • Molecular Sequence Data
  • Pregnancy
  • Pregnancy Proteins / biosynthesis*
  • Pregnancy Proteins / genetics
  • Pregnancy Proteins / immunology
  • RNA, Messenger / isolation & purification
  • Reverse Transcriptase Polymerase Chain Reaction
  • Solubility
  • Trophoblasts / cytology
  • Trophoblasts / immunology
  • Trophoblasts / metabolism*


  • HLA Antigens
  • HLA-G Antigens
  • Histocompatibility Antigens Class I
  • Pregnancy Proteins
  • RNA, Messenger
  • Interferon-gamma