title: Human peripheral blood mononuclear cells (PBMC) in early pregnancy promote embryo invasion in vitro: HCG enhances the effects of PBMC.
abstract: BACKGROUND
  The aim of this study was to investigate the role of peripheral blood mononuclear cells (PBMC) in embryo invasion at the implantation site and to estimate the effect on PBMC function of human chorionic gonadotrophin (HCG) that is secreted from the human embryo.
  
  
  RESULTS
  The effect of PBMC on the invasiveness of murine embryos was examined using an invasion assay. PBMC obtained from women in early pregnancy (5-9 weeks gestation) significantly enhanced both spreading of murine embryos on Matrigel and invasion beneath the gel. These effects were greater than those of PBMC obtained from non-pregnant women in the secretory phase (cycle day 16-24) and the control (in the absence of PBMC). When PBMC obtained from non-pregnant women were incubated with recombinant HCG (10 IU/ml) for 2 days and were subjected to invasion assay using murine embryos, PBMC treated with HCG significantly promoted both spreading and invasion of murine embryos as compared with the non-treated PBMC. On the other hand, embryo outgrowth was not affected by HCG in the absence of PBMC, showing no direct effect of HCG on embryo invasion.
  
  
  CONCLUSIONS
  This study indicated that PBMC from pregnant women promoted murine embryo invasion in vitro and this effect of PBMC was enhanced by HCG. These findings suggest that PBMC at the implantation site are activated by HCG secreted from the embryo, following which PBMC regulate embryo invasion.
authors.affiliation: Department of Gynecology and Obstetrics, Faculty of Medicine, Kyoto University, Sakyo-ku, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakayama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Michiyuki
authors.initials: M
authors.lastname: Maeda
authors.forename: Takuya
authors.initials: T
authors.lastname: Inoue
authors.forename: Shinya
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Takahide
authors.initials: T
authors.lastname: Mori
authors.forename: Shingo
authors.initials: S
authors.lastname: Fujii
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000502:physiology; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D018920:Coculture Techniques; D003094:Collagen; D004338:Drug Combinations; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007797:Laminin; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D051379:Mice; D011247:Pregnancy; D011509:Proteoglycans; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: D006063:Chorionic Gonadotropin; D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; D011994:Recombinant Proteins; C059485:matrigel; D003094:Collagen