Two pregnancy-associated serum proteins with pregnancy-specific {3 1-glycoprotein determinants B. TEISNER
J. G. WESTERGAARD J. FOLKERSEN S. HUSBY
S. E. SVEHAG Odense, DenmiLrk A protein showing strong antigenic cross-reactivity with the "pregnancy-specific" ,8,-glycoprotein (PS/3G) was demonstrated in serum of pregnant women during the second and third trimesters, but not in sera from normal men and nonpregnant women. The described protein had a2·efectrophoretic mobUity and its molecular weight was estimated to be around 200,000 as compared to 80,000 for PS~G. Crossed immunoelectrophoretic analysis, using antiserum to PS,BG, indicated the presence of additional antigenic determinants in PS,BG not demonstrable in the cross-reacting a2-protein. The PSJ3G/a2·protein ratio was rather constant in consecutive serum samples from one woman during pregnancy, but showed a marked variation when sera from different women were compared. Results of rocket immunoelectrophoresis gave a rough estimate of the ratio between these two proteins in a sample of pregnancy serum. The reported findings point to the need for del(elopment of specific methods for quantitatlon of the two proteins and the necessity to re-evaluate earlier quantitative PSt3G date. (AM. J. OBSTET. GYNECOL. 131: 262, 1978.)
PREGNANCY-SPECIFIC {3 1-gJycoprotein (PS{3G), also designated SPl and PAPP-C, has a reported molecular weight of between 85,000 and 110,000. 1• 2 It has been suggested that PS{3G is produced in the trophoblast and its concentration in maternal serum is known to increase gradually during pregnancy. 3- 5 PS{3G has not been demonstrable in serum of normal men and normal nonpregnant women, but was detected by highly sensitive methods in sera from patients with trophoblastic and nontrophoblastic tumors. 6 The biologic function of PS{3G during pregnancy is still unknown but its usefulness as an indicator of placental function has been emphasized. 1• 5 Most quantitative determinations of PS{:IG in sera of pregnant women during the second and third trimesters have been performed by immunoprecipitation methods, 1• 3 · 5 From the Institute of Medical Microbiology arui the Department of Obstetrics arui Gynecology, Odense University. Received for publication November 11, 19 77. Acceptedjanuary 13, 1978. Reprint requests: Dr. B. Teisner. Institute of Medical Microbiology, Odense University, 5000 Odense, Denmark.
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but recently, more-sensitive radioimmunoassays that permit quantitation of PS{3G quite early in pregnancy have been developed. 6 The present work has demonstrated the existence of two pregnancy-specific or -associated proteins, both possessing PS{3G antigenic determinants. Materials and methods Sera. A total of 524 consecutive serum samples were obtained from 104 women from the 16th week of pregnancy up to delivery. The samples were stored at -20° C. in small aliquots until time for testing. Electroimmunoassays. Rocket and crossed immunoelectrophoreses were performed in I per cent agarose using rabbit antisera to PS{3G.* The wells received 2 J.Ll of serum or 15 ,t.tl of chromatographic fractions and rocket immunoelectrophoresis was performed in barbital sodium buffer (0.017 ,t.t, pH 8.6) at 2.5 v. per centimeter for 18 hours. Dilutions of a serum pool obtained from pregnant women in the third trimester *Purchased from Behringwerke, Marburg, Germany (batch Nos. 2998 A and 8701 A), and Dakopatts, Copenhagen, Denmark (batch No. 057). 0002·9378/78103131-0262$00.50/0 © 1978 The C. V. Mosby Co.
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and corresponding to Behringwerke's PS/3G standards served as standards. CrosSm pregnant women . St., standard curve; pt., serum samples collected during pregnancy from eight women. Pt. 30 shows a typical type I rocket ; pt. 21, a type II rocket; and pt. 6 7,
J. G. WESTERGAARD J. FOLKERSEN S. HUSBY
S. E. SVEHAG Odense, DenmiLrk A protein showing strong antigenic cross-reactivity with the "pregnancy-specific" ,8,-glycoprotein (PS/3G) was demonstrated in serum of pregnant women during the second and third trimesters, but not in sera from normal men and nonpregnant women. The described protein had a2·efectrophoretic mobUity and its molecular weight was estimated to be around 200,000 as compared to 80,000 for PS~G. Crossed immunoelectrophoretic analysis, using antiserum to PS,BG, indicated the presence of additional antigenic determinants in PS,BG not demonstrable in the cross-reacting a2-protein. The PSJ3G/a2·protein ratio was rather constant in consecutive serum samples from one woman during pregnancy, but showed a marked variation when sera from different women were compared. Results of rocket immunoelectrophoresis gave a rough estimate of the ratio between these two proteins in a sample of pregnancy serum. The reported findings point to the need for del(elopment of specific methods for quantitatlon of the two proteins and the necessity to re-evaluate earlier quantitative PSt3G date. (AM. J. OBSTET. GYNECOL. 131: 262, 1978.)
PREGNANCY-SPECIFIC {3 1-gJycoprotein (PS{3G), also designated SPl and PAPP-C, has a reported molecular weight of between 85,000 and 110,000. 1• 2 It has been suggested that PS{3G is produced in the trophoblast and its concentration in maternal serum is known to increase gradually during pregnancy. 3- 5 PS{3G has not been demonstrable in serum of normal men and normal nonpregnant women, but was detected by highly sensitive methods in sera from patients with trophoblastic and nontrophoblastic tumors. 6 The biologic function of PS{3G during pregnancy is still unknown but its usefulness as an indicator of placental function has been emphasized. 1• 5 Most quantitative determinations of PS{:IG in sera of pregnant women during the second and third trimesters have been performed by immunoprecipitation methods, 1• 3 · 5 From the Institute of Medical Microbiology arui the Department of Obstetrics arui Gynecology, Odense University. Received for publication November 11, 19 77. Acceptedjanuary 13, 1978. Reprint requests: Dr. B. Teisner. Institute of Medical Microbiology, Odense University, 5000 Odense, Denmark.
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but recently, more-sensitive radioimmunoassays that permit quantitation of PS{3G quite early in pregnancy have been developed. 6 The present work has demonstrated the existence of two pregnancy-specific or -associated proteins, both possessing PS{3G antigenic determinants. Materials and methods Sera. A total of 524 consecutive serum samples were obtained from 104 women from the 16th week of pregnancy up to delivery. The samples were stored at -20° C. in small aliquots until time for testing. Electroimmunoassays. Rocket and crossed immunoelectrophoreses were performed in I per cent agarose using rabbit antisera to PS{3G.* The wells received 2 J.Ll of serum or 15 ,t.tl of chromatographic fractions and rocket immunoelectrophoresis was performed in barbital sodium buffer (0.017 ,t.t, pH 8.6) at 2.5 v. per centimeter for 18 hours. Dilutions of a serum pool obtained from pregnant women in the third trimester *Purchased from Behringwerke, Marburg, Germany (batch Nos. 2998 A and 8701 A), and Dakopatts, Copenhagen, Denmark (batch No. 057). 0002·9378/78103131-0262$00.50/0 © 1978 The C. V. Mosby Co.
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and corresponding to Behringwerke's PS/3G standards served as standards. CrosSm pregnant women . St., standard curve; pt., serum samples collected during pregnancy from eight women. Pt. 30 shows a typical type I rocket ; pt. 21, a type II rocket; and pt. 6 7,
