PreImplantation factor (PIF) detection in maternal circulation in early pregnancy correlates with live birth (bovine model)

Reproductive Biology and Endocrinology

Research

Christopher Stamatkin¹  Sivakumar Ramu¹  Roumen G Roussev²  Leo Timms³  Marshall Ruble³  Eytan R Barnea⁴ 

[1] CARI Laboratories, 233 E. Erie Street, #520, 60611, Chicago, Illinois, USA;CARI Laboratories, 233 E. Erie Street, #520, 60611, Chicago, Illinois, USA;Bulgarian Academy of Sciences, 73 Tzarigradsko Shosse, Sofia, Bulgaria;Department of Animal Science, Iowa State University, 2229 Lincoln Way, 50011, Ames, IA, USA;Society for the Investigation of Early Pregnancy (SIEP), 1697 Lark Lane, 08003, Cherry Hill, NJ, USA;BioIncept LLC, 1697 Lark Lane, 08003, Cherry Hill, NJ, USA;

关键词: PreImplantation factor (PIF);    Pregnancy BioMarker;    ELISA;    Live birth;    Pregnancy outcome;    Monoclonal anti-PIF antibody;    Embryo viability;   

DOI  :  10.1186/1477-7827-11-105

 received in 2013-09-19, accepted in 2013-11-12,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundEarly identification of viable pregnancy is paramount for successful reproduction. Detection of specific signals from pre-implantation viable embryos in normal pregnancy circulation would indicate initiation of embryo-maternal interaction and create a continuum to accurately reflect embryo/fetal well-being post-implantation. Viable mammalian embryos secrete PreImplantation Factor (PIF), a biomarker which plays key, multi-targeted roles to promote implantation, trophoblast invasion and modulate maternal innate and adaptive immunity toward acceptance. Anti-PIF monoclonal antibody (mAb-based chemiluminescent ELISA) accurately detects PIF in singly cultured embryos media and its increased levels correlate with embryo development up to the blastocyst stage. Herein reported that PIF levels (ELISA) in early maternal serum correlate with pregnancy outcome.MethodsArtificially inseminated (AI) blind-coded Angus cattle (N = 21-23) serum samples (day10,15 & 20 post-AI) with known calf birth were blindly tested, using both non-pregnant heifers (N = 30) and steer serum as negative controls. Assay properties and anti-PIF monoclonal antibody specificity were determined by examining linearity, spike and recovery experiments and testing the antibody against 234 different circulating proteins by microarray. Endogenous PIF was detected using <3 kDa filter separation followed by anti-PIF mAb-based affinity chromatography and confirmed by ELISA and HPLC. PIF expression was established in placenta using anti-PIF mAb-based IHC.ResultsPIF detects viable pregnancy at day 10 post-AI with 91.3% sensitivity, reaching 100% by day 20 and correlating with live calf birth. All non-pregnant samples were PIF negative. PIF level in pregnant samples was a stringent 3 + SD higher as compared to heifers and steer sera. Assay is linear and spike and recovery data demonstrates lack of serum interference. Anti-PIF mAb is specific and does not interact with circulating proteins. Anti-PIF based affinity purification demonstrates that endogenous PIF is what ELISA detects. The early bovine placenta expresses PIF in the trophoblast layer.ConclusionData herein documents that PIF is a specific, reliable embryo-derived biomarker conveniently detectable in early maternal circulation. PIF ELISA emerges as practical tool to detect viable early pregnancy from day 20 post-AI.

【 授权许可】

Unknown   
© Ramu et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.