In search of early pregnancy factor: Isolation of active polypeptides from pregnant ewes' sera

Isolation and Purification of Early Pregnancy Factor (EPF) in Rat Serum.

“…In sheep, the purified EPF active material had a M. W. of 20 KD from sera 24 h after insemination [4] and of 20 KD and 67 KD from sera at 3 to 8 weeks of gestation [13]. Clarke and Wilson [14] reported that the major rosette inhibition test active form was characterized as a protein with a M. W. of 20 KD, possessed internal disulphide loop(s), and had a tendency to aggregate into oligomers.…”

Early Pregnancy Factor (EPF): A Link between Fertilization and Immunomodulation

“…Maternal (Cavanagh 1984), fetal (Wilson et al 1983) and tumor-derived EPF (Rolfe et al 1983a) appear to have a number of similar properties. The molecules have a monomeric size of 20000-21 000 and exhibit immunological cross-reactivity, i.e.…”

“…EPF has also been found in serum of patients with tumors of germ cell origin (Rolfe et al 1983a). Maternal, fetal and tumor EPF are of similar molecular size, exhibit immunological crossreactivity and give the same responses in the assay for EPF, but preliminary studies have suggested that they may differ in some biochemical characteristics (Wilson et al 1983;Cavanagh 1984; B. E. Rolfe, A. C. Cavanagh and H. Morton, unpublished data). 0004-9417/84/050393$02.00 EPF binds to lymphocytes and in so doing indirectly suppresses immune reactivity both in vivo and in vitro (Noonan et al 1979;Morton et al 1982a;Rolfe et al 1983b).…”

“…However, these three forms do vary in some of their biochemical characteristics. Maternal EPF can be separated by 40% ammonium sulfate into two components , whereas fetal and tumor EPF are resistant to this form of separation (Wilson et al 1983;A. C. Cavanagh, unpublished data).…”

“…Clarke and Wilson (1982) and also Wilson et al (1983) used serum from pregnant sheep as their source of EPF. The period of gestation (1-2 months) during which serum was collected for their study, suggests that the polypetides described represent fetal ('late') EPF.…”