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Evidence of heterogeneity in the antibody response against the platelet antigen 3a; recognition of an 11-mer peptide carrying the HPA-3a polymorphic determinant |
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| Authors: | E. J. de Leon,F-F. Yuan,H. Pearson,C. P. Marquis,& S. M. Mahler |
| Affiliation: | School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia; R&BD, Australian Red Cross Blood Service, Sydney, NSW, Australia; Research Unit of Transfusion Medicine and Immunogenetics, Faculty of Medicine, University of Sydney, Sydney, NSW, Australia; Platelet Immunology Laboratory, Australian Red Cross Blood Service, Sydney, NSW, Australia; Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Qld, Australia |
| Abstract: | Background The immune processes involved in the development of alloantibodies against the human platelet antigens in alloimmune disorders remain unclear. Antibody recognition of the platelet antigens on their respective platelet glycoproteins has been shown to be dependent on glycoprotein conformation. Furthermore, the post-translational modification of glycoproteins adds complexity to the alloantigenic determinants. Methods Nine anti-HPA-3a sera along with several control sera were tested for reactivity to an 11-mer peptide straddling the HPA-3a/b polymorphism. Sera found to specifically recognize the 3a peptide were further assessed by platelet pre-exposure and immunoblotting. Results Three of the nine antisera were found to specifically recognize an 11-mer synthetic 3a peptide by ELISA. Further analysis of all anti-HPA-3a sera by Western blot showed that only those reactive to the 3a peptide were able to bind both reduced and non-reduced GPIIb. Conclusion The results presented in this study provide the first known evidence for the identification of an antibody population capable of recognizing a linear and non-glycosylated form of the HPA-3a epitope. |
| Keywords: | alloantibodies thrombocytopenia human platelet antigens |