The phenotype of human placental macrophages and its variation with gestational age

Am J Pathol. 1988 Dec;133(3):648-59.


The antigenic phenotype of human villous stromal macrophages (M phi s) from first and third trimester placentas was analyzed using a large number of monoclonal antibodies (MAbs) to monocyte (Mo)/M phi-associated cell membrane determinants. The purpose of this study was to investigate M phi phenotypic heterogeneity to create a database for the correlation of M phi phenotype with specific immunologic functions. The results showed that villous stromal mononuclear cells express many cell surface antigens found on Mo and M phi s and that they are morphologically diverse, ranging in appearance from classic Hofbauer cells to spindle-shaped cells with long cytoplasmic processes. Villous stromal M phi s were the numerically dominant cell type in this structure and exhibited some major phenotypic differences from M phi s in other tissues. Comparison of first- and third-trimester placentas revealed variation in antigen expression with increasing gestational age, in particular of class II major histocompatibility complex (MHC) determinants: HLA-DR and HLA-DP antigen density was low on first-trimester villous M phi s and much higher on third-trimester M phi s while HLA-DQ was undetectable in the first trimester but present on cells in third trimester placentas. The CD1 (T6) antigen, found on Langerhans (LH) cells and cortical thymocytes, was detected on villous M phi s by two thirds of the MAbs directed against different epitopes on this determinant. Furthermore, comparison with similar studies of lymphoid tissues showed that villous M phi s and dendritic cells share the expression of a number of other cell surface antigens. Finally, it was shown that M phi s in first- and third-trimester villi exhibit strong reactivity with MAbs (Leu 3a,b) to the CD4 antigen that serves as the receptor for the human immunodeficiency virus (HIV), suggesting that these cells may be a portal of entry or reservoir for this virus in the fetuses of pregnant, HIV+ women.

Publication types

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

MeSH terms

  • Antigenic Variation
  • Antigens, Surface / analysis
  • Female
  • Gestational Age*
  • HLA-D Antigens / biosynthesis
  • Humans
  • Immunohistochemistry
  • Macrophages / immunology*
  • Phenotype
  • Placenta / cytology
  • Placenta / immunology*
  • Pregnancy
  • Receptors, Complement / analysis
  • Receptors, Fc / analysis
  • Receptors, HIV
  • Receptors, Virus / analysis


  • Antigens, Surface
  • HLA-D Antigens
  • Receptors, Complement
  • Receptors, Fc
  • Receptors, HIV
  • Receptors, Virus