Early pregnancy factor: An extracellular chaperonin 10 homologue

Abstract

Summary Early pregnancy factor (EPF) has been identi®ed as a homologue of chaperonin 10 (cpn10) with immunosuppressive and growth factor properties. As a homologue of cpn10, it belongs to the heat shock family of proteins (hsp) but, unlike other members of this family, EPF is detected extracellularly. Early pregnancy factor was ®rst discovered in pregnancy serum by the rosette inhibition test, and the novelty of its discovery was that its presence could diagnose pregnancy within 6±24 h of a fertile mating. As well as being a monitor of the presence of a viable embryo, it is necessary for embryonic survival. In this capacity it acts as both an immunosuppressant and growth factor. Early pregnancy factor is also a product of proliferating primary and neoplastic cells and functions as an autocrine growth factor both in vivo and in vitro. It has a modifying e ect on the outcome of experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis. Early pregnancy factor is considered to be one of the major factors involved in the modi®cation of multiple sclerosis observed during pregnancy.

Heat Shock Protein 10 Inhibits Lipopolysaccharide-induced Inflammatory Mediator Production

“…Anti-Hsp60 antibodies prevented and mimicked Hsp10 inhibitory activity, suggesting that Hsp10 may inhibit pro-inflammatory responses by interacting with extracellular Hsp60. We were unable to confirm earlier reports that Hsp10 has tumor growth factor properties (37)(38)(39)(40)(41). (42) (a kind gift from Prof. D. Hume, University of Queensland) were cultured (43) in the presence of G418 (200 g/ml) for 1 week after recovery from liquid nitrogen and grown as suspension cultures in 25-cm 3 flasks (Greiner Labortechnik, Frickenhausen, Germany).…”

Heat shock protein 10 and signal transduction: a “capsula eburnea” of carcinogenesis?

“…Since then, it was characterized to enter the serum and urine of pregnant women during the first and second trimesters (Morton et al 1977) and to be the principal immunosuppressive agent during pregnancy . Recently, EPF has been shown to be an extracellular homolog of the heat shock protein, Cpn10 (Summers et al 1996;Morton 1998). Further experiments have shown that Cpn10 is a potent stimulator of osteoclast recruitment and bone resorption (Summers et al 1996;Meghji et al 1997;Morton 1998).…”

Counter-current transfer in reproductive biology

“…It was present after 'few hours' in both women and several animal species. For a long time, it was difficult to reproduce the results outside the Australian continent, but early pregnancy factor is now a well-defined substance (Morton 1998, Schafer-Somi 2003. Modern molecular techniques open new pathways for the detection of an early pregnancy factor produced by the zygote in synergism with signal(s) amplified by cumulus and tubal cells (Hunter & Einer-Jensen 2003).…”