title: Unique epitopes of lactoferrin expressed in human cytotrophoblasts involved in immunologic reactions.
abstract: OBJECTIVE
  Lactoferrin is an iron-binding protein that has been implicated in protection against infections and allogeneic recognition reactions and in the control of cell growth. We studied the biochemical characteristics and expression of the unique lactoferrin epitopes (LF(1)) in human placentas.
  
  
  METHODS
  Immunohistologic studies of normal human term placentas were done by using monoclonal antibodies to LF(1). Double-antibody experiments were done by using monoclonal antibodies to markers of inflammation (macrophages, human leukocyte antigen [HLA-DR]). LF(1) was studied immunochemically by using lactoferrin fragments produced by the reaction of lactoferrin with trypsin or N-glycanase.
  
  
  RESULTS
  Anti-LF(1) monoclonal antibodies reacted with most interstitial cytotrophoblasts in the basal plate and with villous cytotrophoblasts of some but not all chorionic villi. Cytotrophoblasts expressing LF(1) were associated with large numbers of HLA-DR-reactive macrophages. Anti-LF(1) monoclonal antibodies reacted with 2 distinct tryptic fragments of lactoferrin, and these reactivities were not affected by treatment with N-glycanase.
  
  
  CONCLUSIONS
  Placental cytotrophoblasts express unique epitopes of lactoferrin (LF(1)). Such expression is increased in the presence of activated macrophages. This expression could be an extraembryonic response to inflammation and maternal allogeneic recognition as an effort to protect trophoblastic cells. The LF(1) epitopes might represent conserved polypeptide epitopes on 2 homologous lobes of lactoferrin.
authors.affiliation: Klinik und Poliklinik für Frauenheilkunde und Geburtshilfe, Klinikum Brosshadern, Ludwig-Maximilians Universität, Munich, Germany.
authors.forename: C J
authors.initials: CJ
authors.lastname: Thaler
authors.forename: C A
authors.initials: CA
authors.lastname: Labarrere
authors.forename: J S
authors.initials: JS
authors.lastname: Hunt
authors.forename: J A
authors.initials: JA
authors.lastname: McIntyre
authors.forename: W P
authors.initials: WP
authors.lastname: Faulk
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D002824:Chorionic Villi / Q000737:chemistry; D000939:Epitopes / Q000032:analysis*; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007781:Lactoferrin / Q000032:analysis / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010446:Peptide Fragments / Q000276:immunology; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011247:Pregnancy; D014327:Trophoblasts / Q000737:chemistry / Q000276:immunology*; D014357:Trypsin / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D006684:HLA-DR Antigens; D010446:Peptide Fragments; D007781:Lactoferrin; D014357:Trypsin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase