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Modulation of the maternal immune system by the pre-implantation embryo

Caroline G Walker12*, Susanne Meier1, Mathew D Littlejohn1, Klaus Lehnert3, John R Roche1 and Murray D Mitchell24

Author Affiliations

1 DairyNZ Ltd., Hamilton, New Zealand

2 Liggins Institute, The University of Auckland, Grafton, New Zealand

3 ViaLactia Biosciences, Auckland, New Zealand

4 UQ Centre for Clinical Research, The University of Queensland, Brisbane, Queensland

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BMC Genomics 2010, 11:474  doi:10.1186/1471-2164-11-474

Published: 13 August 2010



A large proportion of pregnancy losses occur during the pre-implantation period, when the developing embryo is elongating rapidly and signalling its presence to the maternal system. The molecular mechanisms that prevent luteolysis and support embryo survival within the maternal environment are not well understood. To gain a more complete picture of these molecular events, genome-wide transcriptional profiles of reproductive day 17 endometrial tissue were determined in pregnant and cyclic Holstein-Friesian dairy cattle.


Microarray analyses revealed 1,839 and 1,189 differentially expressed transcripts between pregnant and cyclic animals (with ≥ 1.5 fold change in expression; P-value < 0.05, MTC Benjamini-Hochberg) in caruncular and intercaruncular endometrium respectively. Gene ontology and biological pathway analysis of differentially expressed genes revealed enrichment for genes involved in interferon signalling and modulation of the immune response in pregnant animals.


The maternal immune system actively surveys the uterine environment during early pregnancy. The embryo modulates this response inducing the expression of endometrial molecules that suppress the immune response and promote maternal tolerance to the embryo. During this period of local immune suppression, genes of the innate immune response (in particular, antimicrobial genes) may function to protect the uterus against infection.