Purified human early pregnancy factor from preimplantation embryo possesses immunosuppressive properties

Study of EPF-Like Substance(s) Detected in Fertilized Bovine Ovum Culture Medium.

“…Dev. 40: [7][8][9][10][11]1994) E arty pregnancy factor (EPF) was originally detected by Morton et al [1,2] using a modification of the rosette inhibition test [3,4]. Rosette inhibition titer (RIT), as defined by Bach et al [3,4] is the titer to which an anti-lymphocyte serum (ALS) can inhibit rosette formation between lymphocytes and heterologous erythrocytes to less than 75% of the number formed in the absence of ALS.…”

Early Pregnancy Factor: EPF-Like Substance(s) Purified from Pregnant Bovine Ovary and in vitro Fertilized Ovum Culture Medium

“…Also, Nancarrow et al [25] suggested that a substance "zygotin" was released by the fertilized egg, and this stimulates the production of EPF, most probably from the ovary containing the corpus luteum. Moreover, Ikemizu et al [14], Sueoka [16] and Bose et al [15] reported that EPF was detected in fertilized ovum culture medium. From these reports and our results, we hypothesized about the secretion site and function of EPF.…”

“…In the early 1990s, Cavanagh et al [19] indicated that EPF was secreted from the ovary, Sueoka [16] reported that EPF activity in the culture medium of fertilized human ova increased as ova development progressed, and oviduct or cumulus cells did not participate in EPF secretion. Moreover, EPF has been detected in the culture medium of bovine and human fertilized ova [14,15]. Therefore, it is thought that EPF has two forms (i.e., ovarian origin and fertilized ova origin) during the preimplantation period.…”

Release Period of EPF-Like Substance(s) in Rat and Bovine Fertilized Ova.

“…Bose et al [7] reported that the presence of EPF and immunosuppressive activity in the growth media of cleaved ova and its absence in media from unfertilized ova indicates that this factor is indeed a product of the early developing embryo. This factor may interact at the maternal-fetal tissue interface, resulting in the prevention of the activation and proliferation of maternal lymphocytes.…”