The Blood Group I and i Antigens of Amniotic Fluid

Abstract

Human amniotic fluid has been shown to contain blood group i as well as I antigens. Crude extracts of amniotic fluids at 16-23 weeks of gestation were in general more active than those obtained at term. A pool of amniotic fluids which had A, B, H as well as I and i activity was fractionated with an insolubilized anti-I (Group 3 type) immunoadsorbent column. There was evidence for the occurrence of I and i determinants on macromolecules carrying A, B and H determinants, for the fraction specifically retained by the column was enriched by 50-60-fold in I and i activity and by at least 10-fold in A, B and H activity. In the fraction not retained by the column there remained the bulk of the A, B, H activity in addition to I activity of Group I type which is known to be distinct from the Group 3 determinant. With the aid of specific immunochemical fractionation procedures, human amniotic fluid should prove useful in structural studies of the several I and i determinants and of their relationship to other blood group determinants.

Blood-group-Ii-active gangliosides of human erythrocyte membranes

“…The details of the method will be described elsewhere. Briefly, a glycoprotein-rich extract was prepared from a sample of human meconium by digestion with pepsin and precipitation with ethanol as described by Feizi et al (1975). The extract was labelled with 1251 by the chloramine-T method (Greenwood et al, 1963) and enriched for blood-group-I and -i activities by affinity chromatography on an adsorbent made with an anti-(blood-group I) antibody coupled to Sepharose 2B .…”

Blood-group-I activity associated with band 3, the major intrinsic membrane protein of human erythrocytes

“…respectively) in 6ml ofequilibration buffer (10mM-Tris/HCl, pH 8.2, containing 1 % Empigen, 0.02% SDS, 0.1 % bovine serum albumin and 0.02,% sodium azide) was passed through an anti-(blood-group I) or a control column. The former contained 50mg of antibody (a macroglobulin) isolated from the serum of a patient (Low) and coupled to 5rml of Sepharose 2B as described by Feizi et al (1975), The control adsorbent contained 50mg of a Waldenstrom macroglobulin without anti-(blood-group I) activity. Adsorption was carried out at 4°C (flow rate, 2ml/h); unbound material was removed by washing with equilibration buffer at 4°C (flow rate, 40m1/h); bound material was eluted in two steps by washing with (1) equilibration buffer at 37°C and (2) equilibration buffer containing I M-NaI at 4°C.…”

Sheep gastric mucins as a source of blood-group-I and -i antigens

“…Preparation of glycoprotein extracts from stomach mucosae Fresh adult sheep stomachs (abomasa) were obtained at slaughter from a local abattoir. Glycoprotein-rich extracts of the mucosal scrapings from individual stomachs were prepared after digestion with pepsin as described previously (Bendich et al, 1946;Feizi et al, 1975). Aqueous solutions thus obtained were extracted twice with 2vol.…”

“…Previous studies with blood-group substances (Lloyd & Kabat, 1968) have indicated that one cycle of Smith degradation results in the destruction of only the terminal monosaccharides (also subterminal galactose residues in blood-group-H substance).Thus the following predictions would apply: terminal (non-reducing) galactose residues of precursor chains, terminal fucose and N-acetylgalactosamine residues of blood-group-A substances, and terminal fucose residues and subterminal galactose residues of blood-group-H substances would be destroyed. Affinity chromatography ofsheep glycoproteins An adsorbent made from the anti-(blood group I) antibody of patient Low was as described by Feizi et al (1975), and contained approx. 850mg of antibody protein coupled to 85 ml of Sepharose 4B.…”