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标题：Combined transgenic expression of α-galactosidase and α1,2-fucosyltransferase leads to optimal reduction in the major xenoepitope Galα(1,3)Gal
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作者：Narin Osman ; Ian F. C. McKenzie ; Karen Ostenried 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1997
卷号：94
期号：26
页码：14677-14682
DOI：10.1073/pnas.94.26.14677
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Hyperacute rejection of pig organs by humans involves the interaction of Gal(1,3)Gal with antibodies and complement. Strategies to reduce the amount of xenoantigen Gal(1,3)Gal were investigated by overexpression of human lysosomal -galactosidase in cultured porcine cells and transgenic mice. The overexpression of human -galactosidase in cultured porcine endothelial cells and COS cells resulted in a 30-fold reduction of cell surface Gal(1,3)Gal and a 10-fold reduction in cell reactivity with natural human antibodies. Splenocytes from transgenic mice overexpressing human -galactosidase showed only a 15-25% reduction in binding to natural human anti-Gal(1,3)Gal antibodies; however, this decrease was functionally significant as demonstrated by reduced susceptibility to human antibody-mediated lysis. However, because there is residual Gal(1,3)Gal and degalactosylation results in the exposure of N-acetyllactosamine residues and potential new xenoepitopes, using -galactosidase alone is unlikely to overcome hyperacute rejection. We previously reported that mice overexpressing human 1,2-fucosyltransferase as a transgene had {approx}90% reduced Gal(1,3)Gal levels due to masking of the xenoantigen by fucosylation; we evaluated the effect of overexpressing -galactosidase and 1,2-fucosyltransferase on Gal(1,3)Gal levels. Gal(1,3)Gal-positive COS cells expressing 1,3-galactosyltransferase, 1,2-fucosyltransferase, and -galactosidase showed negligible cell surface staining and were not susceptible to lysis by human serum containing antibody and complement. Thus, 1,2-fucosyltransferase and -galactosidase effectively reduced the expression of Gal(1,3)Gal on the cell surface and could be used to produce transgenic pigs with negligible levels of cell surface Gal(1,3)Gal, thereby having no reactivity with human serum and improving graft survival.