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Immune recognition of exposed xenoantigens on the surface of PEGylated bovine red blood cells
Author(s) -
Gundersen Sharon I.,
Kennedy Melanie S.,
Palmer Andre F.
Publication year - 2008
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.21908
Subject(s) - pegylation , flow cytometry , agglutination (biology) , chemistry , immune system , antibody , peg ratio , polyethylene glycol , immunology , biochemistry , biology , finance , economics
Due to potential problems that can occur during blood transfusion and increasing blood shortages, our group engineered methoxypolyethylene glycol conjugated bovine red blood cells (mPEG‐bRBCs) as a potential universal oxygen therapeutic. This current work investigates the immunological properties of mPEG‐bRBCs incubated with human plasma (hP) and correlates these properties to exposed Galα(1,3)Gal xenoantigens. After mPEG‐bRBCs were incubated with hP, the amount of bound IgG and IgM was assessed via flow cytometry. Flow cytometry also assessed the amount of GS‐IB4 bound to exposed Galα(1,3)Gal xenoantigens. The results of this study demonstrate that most hP samples strongly promote agglutination of mPEG‐bRBCs regardless of the extent of mPEG surface coverage or donor blood type. IgG and IgM from hP bound strongly to mPEG‐bRBCs. In general, the Galα(1,3)Gal xenoantigen remains exposed at all levels of PEG surface coverage. PEGylation did block some of the xenoantigens as the amount of exposed Galα (1,3)Gal decreased with increased mPEG surface coverage. However, this was not sufficient to prevent a strong agglutination reaction. Taken together, the results of this study indicate that the current strategy for PEGylating bRBCs is unsatisfactory for the development of immunologically silent oxygen therapeutics. Biotechnol. Bioeng. 2008;101: 337–344. © 2008 Wiley Periodicals, Inc.