title: Transplacental priming of the human immune system with environmental allergens can occur early in gestation.
abstract: BACKGROUND
  Allergen-specific T cells play an important role in the allergic immune response to various environmental allergens. In vitro studies have shown that T-cell responses to these allergens do occur prenatally. Some allergens (milk proteins) appear to lead more often to fetal T-cell priming than others (house dust mite allergen, ovalbumin, and birch and grass pollen allergens).
  
  
  OBJECTIVE
  We sought to determine the window of opportunity for prenatal T-cell priming with inhalant and nutritive allergens.
  
  
  METHODS
  The T-cell reactivity of cord blood cells derived through cordocentesis from unborn (n = 62) and term babies (n = 114) in response to inhalant allergens (birch pollen major allergen, recombinant Bet v 1, and timothy grass major allergen, recombinant Phl p 1) was investigated.
  
  
  RESULTS
  The results demonstrate that allergen-specific T-cell reactivity is as common in preterm as in term infants (Bet v 1, 8% and 5%, respectively; Phl p 1, 20% and 25%, respectively).
  
  
  CONCLUSIONS
  Our data support the hypothesis that differential handling of the allergenic proteins by the feto-placental barrier and possibly by antigen-presenting cells may directly modulate the ensuing T-cell immune response.
authors.affiliation: Department of Pediatrics, University of Vienna, Vienna, Austria.
authors.forename: Z
authors.initials: Z
authors.lastname: Szépfalusi
authors.forename: J
authors.initials: J
authors.lastname: Pichler
authors.forename: S
authors.initials: S
authors.lastname: Elsässer
authors.forename: K
authors.initials: K
authors.lastname: van Duren
authors.forename: C
authors.initials: C
authors.lastname: Ebner
authors.forename: G
authors.initials: G
authors.lastname: Bernaschek
authors.forename: R
authors.initials: R
authors.lastname: Urbanek
mesh_terms: D000280:Administration, Inhalation; D000393:Air Pollutants / Q000276:immunology*; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D004781:Environmental Exposure; D000939:Epitopes; D005260:Female; D005312:Fetal Blood / Q000737:chemistry / Q000166:cytology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation / Q000276:immunology; D008431:Maternal-Fetal Exchange; D011247:Pregnancy
chemical_list: D000393:Air Pollutants; D000485:Allergens; D000939:Epitopes; D007376:Interleukin-2