Detection and Partial Characterization of Two Bovine Pregnancy-Specific Proteins12

Abstract

Two pregnancy-specific proteins were detected by immunoelectrophoresis using antisera developed to homogenates of bovine extraembryonic membranes. Antisera also reacted to extracts of endometrium from pregnant cows and extraembryonic fluids. However, antisera did not react with a preparation presumed to be bovine placental lactogen, fetuin, extracts of various somatic tissues from pregnant cows or extracts of endometrium from nonpregnant cows. One of the proteins had an estimated molecular weight of 65,000-70,000, an isoelectric point of 4.6-4.8 and yielded a reaction of identity with bovine alpha 1-fetoprotein by immunodiffusion. The second protein yielded a reaction of identity with bovine alpha 1-fetoprotein by immunodiffusion. The second protein had no immunological cross-reactivity with the known proteins or organ extracts which were tested. The molecular weight and isoelectric point was 47,000-53,000 and 4.0-4.4, respectively. These data demonstrate the presence of at least 2 pregnancy-specific proteins in cattle.

Biodiversity of multiple Pregnancy-Associated Glycoprotein (PAG) family: gene cloning and chorionic protein purification in domestic and wild eutherians (Placentalia) – a review

“…The first member of the family was described by Butler et al [1] and was given initially the name pregnancy specific protein B (PSPB) in bovine placenta. Subsequent work by other research groups identified related proteins, which were given names such as PAGs [2,3], 60 kDa -pregnancy serum protein (PSP60) [4], or SBU3 [5] in ruminant ungulates (see Sect.…”

“…However, the production of polyclonal and monoclonal antisera requires species-specific antigens, thus harvesting various placental PAG proteins. Initially, anti-PAG sera were produced against semi-purified chorionic antigens, then the obtained semi-specific antisera were purified by adsorption with various bovine tissues harvested from nonpregnant animals [1]. Later, a few potential protein sources were utilised for production of placental antigens (Tab.…”

Isolation and characterization of eight pregnancy-associated glycoproteins present at high levels in the ovine placenta between day 60 and day 100 of gestation

“…They were purified from cattle placentae and are also found in the maternal blood serum soon after embryo implantation [3]. These glycoproteins were later proven to be closely related to bovine PSPB (Pregnancy Specific Protein B) [4], isolated as early as 1982 by Butler et al [5]. In sheep, PAG called ovPAG [2], SBU-3 [6], or oPSPB [7] were identified mainly by three different approaches.…”

Peripheral concentrations of a 60-kDa pregnancy serum protein during gestation and after calving and in relationship to embryonic mortality in cattle

“…Another signal of pregnancy in the serum is PSPB (pregnancy specific protein B). This has been partially characterized in cattle by Butler et al (1982) (Crock et al, 1988). Radioimmunoassay (RIA) of PSPB enables the course of the pregnancy or late embryonic mortality to be studied (Humblot et al, 1988a, b) (Zoli et al, 1992a).…”