title: Comparative T-cell responses during pregnancy in large animals and humans.
abstract: OBJECTIVE
  Placentation in different large animal species shows a remarkable diversity in the level of trophoblast invasion into the maternal endometrial tissues. We wish to determine the influence of implantation on T-cell responses during pregnancy.
  
  
  METHODS
  Review of the literature and current data.
  
  
  RESULTS
  alphabeta-TCR+ T cells are only prominent during early pregnancy in species with relatively non-invasive placentation (pig and horse) but are rapidly downregulated in species with more invasive placentae. gammadelta-TCR+ T cells are prominent in species with moderate trophoblast invasion (ruminants) where they increase dramatically during mid and late pregnancy. gammadelta-TCR+ T cells remain prominent during late gestation in species with highly invasive placentation (humans) and, in addition, a distinct gammadelta T-cell population is present in first trimester decidua where it may play a regulatory role in controlling natural killer cell activity. The gammadelta-TCR+ population present in both ruminants and humans shows large granular morphology and contains antimicrobial proteins, suggesting their function may be to protect the uterine environment from infection during pregnancy and parturition.
  
  
  CONCLUSIONS
  The comparative analysis of T-cell responses during pregnancy in different large animal species supports an increasing role for cells of the innate immune response (NK and gammadelta T cells) and a downregulation of the adaptive immune response with increasingly invasive placentation.
authors.affiliation: Centre for Animal Biotechnology, School of Veterinary Science, The University of Melbourne, Victoria, Australia. e.meeusen@unimelb.edu.au
authors.forename: E N
authors.initials: EN
authors.lastname: Meeusen
authors.forename: R J
authors.initials: RJ
authors.lastname: Bischof
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D007107:Immune System / Q000276:immunology; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D011247:Pregnancy / Q000276:immunology*; D011270:Pregnancy, Animal / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors
chemical_list: D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta