Terminal sialic acid residues on human glycophorin A are recognized by porcine Kupffer cells

Christopher Burlak, Lisa M. Twining, Michael A. Rees

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Background. We have previously shown that recognition of human erythrocytes by porcine Kupffer cells is mediated by a carbohydrate-dependent mechanism. The present study explores the possible ligands existing on human glycophorin A and tests their ability to inhibit erythrocyte rosette formation. Methods. Human erythrocytes were tested for ABO and MN specificity and used as targets in a 51Chromium quantitative erythrocyte rosette assay. Monosaccharides present on human glycophorin A, neuraminyl lactoses, bovine and porcine submaxillary mucins (BSM and PSM), and hyaluronic acid as well as proteoglycan N-linked glycosidase F(PNGaseF)- and sialidase A-treated human erythrocyte glycoproteins (hEGP) and human erythrocytes were all tested for inhibitory potential in the resetting assay. Results. Porcine Kupffer-cell recognition of human erythrocytes was insensitive to differences in blood groups A, B, O, or MN. At 30 mM, the monosaccharide, N-acetylneuraminic acid, and the trisaccharide mixture, neuraminyl lactoses, disrupted human erythrocyte recognition by 25% and 30%, respectively. A dilution of BSM but not PSM inhibited the rosetting assay by 17% (.2 mg/mL), 33% (1 mg/mL), and 53% (2 mg/mL). The same dilution of hyaluronic acid had no effect on rosetting. Removal of N-linked oligosaccharides from hEGP with PNGaseF did not impair its ability to inhibit the rosetting assay. In contrast, removal of sialic acid completely abrogated its inhibitory ability. Treatment of whole human erythrocytes with sialidase A likewise prevented recognition by porcine Kupffer cells. Conclusions. Terminal sialic acid on human erythrocytes is a target recognized by porcine Kupffer cells, suggesting a role for a sialic-acid receptor in innate cellular recognition of xenogeneic epitopes. Inasmuch as this work reveals a carbohydrate-recognition mechanism for cellular rejection, we shed light on a potential newboundary that will need to be overcome within xenotransplantation.

Original languageEnglish (US)
Pages (from-to)344-352
Number of pages9
Issue number3
StatePublished - Aug 15 2005


  • Extracorporeal perfusion
  • Glycophorin A
  • N-acetylneuraminic acid
  • Sialic acid
  • Xenogeneic


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