K. Ridgwell

The Rhesus (D) polypeptide is linked to the human erythrocyte cytoskeleton

Cytoskeleton preparations derived from lactoperoxidase‐radioiodinated human erythrocytes were found to be enriched in a labelled component with the same apparent molecular mass as the Rhesus (D) (Rh(D)) antigen polypeptide. Immune precipitation from the cytoskeleton preparations confirmed that this component is the Rh(D) polypeptide. The results suggest that the Rh(D) polypeptide may be linked to the erythrocyte skeletal matrix. The possibility that the Rh(D) antigen is involved in maintaining the shape and viability of the erythrocyte is discussed.

South-east Asian ovalocytic (SAO) erythrocytes have a cold sensitive cation leak: Implications for in vitro studies on stored SAO red cells

South-east Asian ovalocytosis (SAO) results from the heterozygous presence of an abnormal band 3, which causes several alterations in the properties of the erythrocytes. Although earlier studies suggested that SAO erythrocytes are refractory to invasion in vitro by the malarial parasite Plasmodium falciparum, a more recent study showed that fresh SAO cells were invaded by the parasites, but became resistant to invasion on storage because intracellular ATP was depleted more rapidly than normal. Here we show that SAO red cells are much more leaky to sodium and potassium than normal red cells when stored in the cold. This leak was much less marked when the cells were stored at 25 or 37 degreesC. Incubation for 3.5 h at 37 degreesC of cold-stored SAO red cells did not restore sodium and potassium to normal levels, probably because the depleted ATP level in cold-stored SAO red cells is further reduced with incubation at 37 degreesC. The increased leakiness of SAO red cells is non-specific and extends to calcium ions, taurine, mannitol and sucrose. These results suggest that SAO red cells undergo a structural change on cooling. Since many of the reports describing altered properties of SAO red cells have used cells which have been stored in the cold, these results need re-evaluation using never-chilled SAO red cells to assess whether the cells have the same abnormal properties under in vivo conditions.

Effect of endoglycosidase F-peptidyl N-glycosidase F preparations on the surface components of the human erythrocyte

Endo-N-acetyl-beta-D-glucosaminidase F-Peptidyl N-glycosidase F preparations (abbreviated Endo F) and endo-beta-D-galactosidase were used to study the major human erythrocyte membrane glycoproteins and the components carrying the blood group A, B, Rhesus (D), and Duffy (Fya) antigens. The results are consistent with the known presence of an N-glycosyl-linked oligosaccharide on sialoglycoprotein alpha and the absence of such an oligosaccharide from sialoglycoprotein delta. Under the conditions used, only a portion of the N-glycosyl-linked oligosaccharides on band 3 molecules were cleaved by Endo F alone or by Endo F in combination with endo-beta-D-galactosidase. Immunoblotting experiments showed that treatment of red cells with Endo F alone had little effect on the components carrying blood group A and B antigen activity. However, Endo F used in combination with endo-beta-D-galactosidase caused a substantial reduction in the binding of monoclonal anti-A and anti-B antibodies. The results clearly show that sialoglycoproteins alpha and delta carry little or no blood group A or B activity. Endo F alone, or in combination with endo-beta-D-galactosidase, had no effect on the electrophoretic mobility of the Rh(D) polypeptide, supporting previous suggestions that this membrane polypeptide is unusual in not being glycosylated. Endo F had a dramatic effect on the electrophoretic mobility of the component(s) carrying blood group Fya activity. The diffuse Fya component of Mr 38,500-90,000 was sharpened to a band of Mr 26,000. Either endo-beta-D-galactosidase or neuraminidase treatment reduced the Mr of the Fya component(s) but did not significantly sharpen the bands, suggesting that the Fya component contains between 40-50% by mass of N-glycosyl-linked oligosaccharides.

The Low‐Incidence Blood Group Antigen, Wda, Is Associated with the Substitution Val557→ Met in Human Erythrocyte Band 3 (AE1)

The Waldner blood group antigen (Wda) was first identified in members of a Hutterite kindred. Evidence that the gene governing the Waldner polymorphism is located on chromosome 17, and the observation that the antigen is inactivated by chymotrypsin prompted the investigation of a possible association between Wda and band 3. Single Stranded Conformational Polymorphism (SSCP) analysis and DNA sequence analysis of the AE1 gene, from subjects of known Waldner phenotypes, showed a heterozygous mutation leading to the substitution Val557→ Met in the presumptive Wd(a+) heterozygotes. Therefore the Wda blood group antigen is associated with the presence of Met557 on band 3. The Waldner antigen has been assigned to the Diego blood group system with the International Society of Blood Transfusion number DI5.

SHORT COMMUNICATIONS: THE Wrb ANTIGEN IN Sta‐POSITIVE AND DANTU‐POSITIVE HUMAN ERYTHROCYTES

Immunoprecipitation using a monoclonal antibody showed that the Wrb antigen is present on the abnormal (δ‐α) hybrid sialoglycoprotein of Sta‐positive human erythrocytes but not on the abnormal (δ‐α) hybrid sialoglycoprotein of Dantu‐positive erythrocytes. These results provide further information regarding the nature and location of the Wrb antigen on the normal erythrocyte sialoglycoprotein α.