The transfer of bovine J blood group activity to erythrocytes: evidence of a transferable and of a non‐transferable J in serum

Abstract

Keywords: blood group J, bovine blood, erythrocytes, transfer of J The J blood group substance of cattle is primarily a soluble substance in the blood plasma and is secondarily transferred to the erythrocyte membrane in vivo (Stormont, 1949) and in vitro (Stone, 1962). The J activity of plasma is found both in the lipid fraction and in the solid residue left after lipid extraction of serum (Schroffel et al., 1971). The residue contains the bulk of denatured serum proteins. It was demonstrated that the J activity is transferred from this J-positive residue ('J donor') to J-negative erythrocytes ('J acceptor') by a simple incubation procedure in a buffered medium (Krotlinger, Thiele & Ohl, 1976). However, the transfer of J activity from the serum lipid fraction to erythrocytes is very inefficient, if at all detectable. This poor transfer is probably due to the presence of a blocking substance (Blakeslee & Stone, 1971) which is a mixture of phospholipids (Stephan & Thiele, 1978).The solid residue which served as the J donor in earlier experiments was almost insoluble in water or saline. Therefore, attempts were made to prepare a soluble Jactive fraction from this residue. Repeated extractions with 1 mmol/l phosphate buffer (pH 7.4) succeeded in a solubilization of about 2/3 of the protein together with J activity. Another successful procedure consisted in boiling the solid residue with saline followed by centrifugation (Slomiany , Slomiany & Horowkz, 1973). The J activity of the supernatant (termed 'heat-stable extract') was enriched up to 35-fold (compared to the protein content). The quantification of J activityin terms of antigen units, UAhOof red cells as well as of serum or of dissolved samples was described in detail recently (Oulevey, Wagner & Thiele, 1982). These prerequisites allowed kinetic studies of the J transfer from solubilized J donors to J-negative red cells or stroma. Generally, buffer extract or heat-stable extract of known J activity (ranging between approx. 400 and approx. 11000 Uiio) was mixed with isotonic phosphate buffer (pH 7.4) and with a suspension of washed Animal Blood Groups and Biochemical Generics 15 (1984) Animal Blood Groups and Biochemical Generics 15 (I 984) of erythrocytes with soluble J substance from serum. Vox Sanguinis 21: 269-283. cattle erythrocytes. Blur 37: 201-209.