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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Immunol. | doi: 10.3389/fimmu.2018.03025

Immunological homeostasis at the ovine placenta may reflect the degree of maternal foetal interaction

  • 1Vaccines Department, Moredun Research Institute, United Kingdom
  • 2Centre for Dementia Prevention, The University of Edinburgh, 9A Bioquarter, 9 Little France Road, Edinburgh, Scotland, United Kingdom, EH16 4UX, United Kingdom
  • 3Department of Microbiology and Immunology, Schulich School of Medicine & Dentistry, University of Western Ontario, Canada
  • 4School of Applied Sciences, Edinburgh Napier University, United Kingdom
  • 5Triveritas Ltd, Bank Barn, How Mill, Brampton, Cumbria, Northern Ireland
  • 6University College London Hospital, 235 Euston Road, United Kingdom
  • 7Instituto de Ganadería de Montaña (IGM), Spain
  • 8Biomathematics and Statistics Scotland, United Kingdom
  • 9Roslin Institute, University of Edinburgh, United Kingdom

Successful mammalian pregnancies are a result of complex physiological, endocrinological and immunological processes that combine to create an environment where the mother is tolerant to the semi-allogeneic fetus. Our knowledge of the mechanisms that contribute to maternal tolerance is derived mainly from human and murine studies of haemochorial placentation. However, as this is the most invasive type of placentation it cannot be assumed that identical mechanisms apply to the less invasive epitheliochorial placentation found in other species such as ruminants. Here, we examine three features associated with reproductive immune regulation in a transformed ovine trophoblast cell line and ex-vivo ovine reproductive tissues collected at term, namely: major histocompatibility complex (MHC) expression, Indoleamine 2, 3 dioxygenase-1 (IDO-1) expression and Natural Killer (NK) cell infiltration. High levels of MHC class I protein expression were detected at the surface of the trophoblast cell line using a pan-MHC class I specific monoclonal antibody. The majority of MHC class I transcripts isolated from the cell line clustered with classical MHC alleles. Transcriptional analysis of placental tissues identified only classical MHC class I transcripts. We found no evidence of constitutive transcription of IDO-1 in either the trophoblast cell line or placental tissues. Ex-vivo tissues collected from the materno-fetal interface were negative for cells expressing NKp46/NCR1. Collectively, these observations suggest that the relatively non-invasive synepitheliochorial placentation found in sheep has a more limited requirement for local immunoregulation compared to the more invasive haemochorial placentation of primates and rodents.

Keywords: Ovine, Major Histocompatibility Complex, Indoleamine 2, 3 dioxygenase-1, synepitheliochorial placentation, trophoblast

Received: 28 Sep 2018; Accepted: 06 Dec 2018.

Edited by:

Robert D. Miller, University of New Mexico, United States

Reviewed by:

Michelle Baker, Australian Animal Health Laboratory (CSIRO), Australia
Oliver W. Griffith, The University of Melbourne, Australia  

Copyright: © 2018 Wattegedera, Doull, Goncheva, Wheelhouse, Watson, Pearce, Benavides, Palarea-Albaladejo, McInnes, Ballingall and Entrican. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Mr. Sean R. Wattegedera, Moredun Research Institute, Vaccines Department, Penicuik, United Kingdom, sean.wattegedera@moredun.ac.uk
Dr. Julio Benavides, Instituto de Ganadería de Montaña (IGM), León, 24346, Spain, julio.benavides.silvan@csic.es
Dr. Colin J. McInnes, Moredun Research Institute, Vaccines Department, Penicuik, United Kingdom, colin.mcinnes@moredun.ac.uk