Editing GroES (section)

== Origin ==

Early embryos are not believed to directly produce EPF. Rather, embryos are believed to produce some other chemical that induces the maternal system to create EPF.<ref>{{cite journal | vauthors = Orozco C, Perkins T, Clarke FM | title = Platelet-activating factor induces the expression of early pregnancy factor activity in female mice | journal = Journal of Reproduction and Fertility | volume = 78 | issue = 2 | pages = 549–55 | date = Nov 1986 | pmid = 3806515 | doi = 10.1530/jrf.0.0780549 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Roberts TK, Adamson LM, Smart YC, Stanger JD, Murdoch RN | title = An evaluation of peripheral blood platelet enumeration as a monitor of fertilization and early pregnancy | journal = Fertility and Sterility | volume = 47 | issue = 5 | pages = 848–54 | date = May 1987 | pmid = 3569561 | doi = 10.1016/S0015-0282(16)59177-8 }}</ref><ref>{{cite journal | vauthors = Sueoka K, Dharmarajan AM, Miyazaki T, Atlas SJ, Wallach EE | title = Platelet activating factor-induced early pregnancy factor activity from the perfused rabbit ovary and oviduct | journal = American Journal of Obstetrics and Gynecology | volume = 159 | issue = 6 | pages = 1580–4 | date = Dec 1988 | pmid = 3207134 | doi = 10.1016/0002-9378(88)90598-4 }}</ref><ref>{{cite journal | vauthors = Cavanagh AC, Morton H, Athanasas-Platsis S, Quinn KA, Rolfe BE | title = Identification of a putative inhibitor of early pregnancy factor in mice | journal = Journal of Reproduction and Fertility | volume = 91 | issue = 1 | pages = 239–48 | date = Jan 1991 | pmid = 1995852 | doi = 10.1530/jrf.0.0910239 | citeseerx = 10.1.1.578.5819 }}</ref><ref>{{cite journal | vauthors = Cavanagh AC, Rolfe BE, Athanasas-Platsis S, Quinn KA, Morton H | title = Relationship between early pregnancy factor, mouse embryo-conditioned medium and platelet-activating factor | journal = Journal of Reproduction and Fertility | volume = 93 | issue = 2 | pages = 355–65 | date = Nov 1991 | pmid = 1787455 | doi = 10.1530/jrf.0.0930355 | doi-access = free }}</ref> After implantation, EPF may be produced by the conceptus directly.<ref name="origin" />

EPF is an immunosuppressant. Along with other substances associated with early embryos, EPF  is believed to play a role in preventing the [[immune system]] of the pregnant female from attacking the embryo.<ref name="immuno1980" /><ref>{{cite journal | vauthors = Bose R, Cheng H, Sabbadini E, McCoshen J, MaHadevan MM, Fleetham J | title = Purified human early pregnancy factor from preimplantation embryo possesses immunosuppresive properties | journal = American Journal of Obstetrics and Gynecology | volume = 160 | issue = 4 | pages = 954–60 | date = Apr 1989 | pmid = 2712125 | doi = 10.1016/0002-9378(89)90316-5 }}</ref> Injecting anti-EPF antibodies into mice after mating significantly {{quantify|date=August 2008}} reduced the number of successful pregnancies and number of pups;<ref>{{cite journal | vauthors = Igarashi S | title = [Significance of early pregnancy factor (EPF) on reproductive immunology] | journal = Nihon Sanka Fujinka Gakkai Zasshi | volume = 39 | issue = 2 | pages = 189–94 | date = Feb 1987 | pmid = 2950188 }}</ref><ref>{{cite journal | vauthors = Athanasas-Platsis S, Quinn KA, Wong TY, Rolfe BE, Cavanagh AC, Morton H | title = Passive immunization of pregnant mice against early pregnancy factor causes loss of embryonic viability | journal = Journal of Reproduction and Fertility | volume = 87 | issue = 2 | pages = 495–502 | date = Nov 1989 | pmid = 2600905 | doi = 10.1530/jrf.0.0870495 | doi-access = free }}</ref> no effect on growth was seen when mice embryos were cultured in media containing anti-EPF antibodies.<ref>{{cite journal | vauthors = Athanasas-Platsis S, Morton H, Dunglison GF, Kaye PL | title = Antibodies to early pregnancy factor retard embryonic development in mice in vivo | journal = Journal of Reproduction and Fertility | volume = 92 | issue = 2 | pages = 443–51 | date = Jul 1991 | pmid = 1886100 | doi = 10.1530/jrf.0.0920443 | doi-access = free }}</ref>  While some actions of EPF are the same in all mammals (namely rosette inhibition), other immunosuppressant mechanism vary between species.<ref>{{cite journal | vauthors = Rolfe BE, Cavanagh AC, Quinn KA, Morton H | title = Identification of two suppressor factors induced by early pregnancy factor | journal = Clinical and Experimental Immunology | volume = 73 | issue = 2 | pages = 219–25 | date = Aug 1988 | pmid = 3180511 | pmc = 1541604 }}</ref>

In mice, EPF levels are high in early pregnancy, but on day 15 decline to levels found in non-pregnant mice.<ref>{{cite journal | vauthors = Takimoto Y, Hishinuma M, Takahashi Y, Kanagawa H | title = Detection of early pregnancy factor in superovulated mice | journal = Nihon Juigaku Zasshi. The Japanese Journal of Veterinary Science | volume = 51 | issue = 5 | pages = 879–85 | date = Oct 1989 | pmid = 2607739 | doi = 10.1292/jvms1939.51.879 | doi-access = free }}</ref> In humans, EPF levels are high for about the first twenty weeks, then decline, becoming undetectable within eight weeks of [[childbirth|delivery]].<ref>{{cite journal | vauthors = Qin ZH, Zheng ZQ | title = Detection of early pregnancy factor in human sera | journal = American Journal of Reproductive Immunology and Microbiology | volume = 13 | issue = 1 | pages = 15–8 | date = Jan 1987 | pmid = 2436493 | doi=10.1111/j.1600-0897.1987.tb00082.x}}</ref><ref>{{cite journal | vauthors = Wang HN, Zheng ZQ | title = Detection of early pregnancy factor in fetal sera | journal = American Journal of Reproductive Immunology | volume = 23 | issue = 3 | pages = 69–72 | date = Jul 1990 | pmid = 2257053 | doi = 10.1111/j.1600-0897.1990.tb00674.x | s2cid = 221409934 }}</ref>