Reduction in the level of Gal(alpha1,3)Gal in transgenic mice and pigs by the expression of an alpha(1,2)fucosyltransferase.

Sharma, Ajay; Okabe, Jeannine; Birch, Patrick; McClellan, Steven; Martin, Michael; Platt, Jeffrey L.; Logan, John S.

doi:10.1073/pnas.93.14.7190

Cited by 183 publications

(91 citation statements)

References 27 publications

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“…However, this strategy was not as effective in the several transgenic pig lines that were generated (51)(52)(53). This may reflect higher levels of Gal␣(1,3)Gal in pigs, but we propose that the residual Gal␣(1,3)Gal observed in ␣1,2FT transgenic pigs is partly due to iGb3S.…”

Section: Previous Studies Of Ggta1mentioning

confidence: 58%

The Molecular Basis for Galα(1,3)Gal Expression in Animals with a Deletion of the α1,3Galactosyltransferase Gene

Milland

Christiansen

Lazarus

et al. 2006

The Journal of Immunology

104

105

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The production of homozygous pigs with a disruption in the GGTA1 gene, which encodes α1,3galactosyltransferase (α1,3GT), represented a critical step toward the clinical reality of xenotransplantation. Unexpectedly, the predicted complete elimination of the immunogenic Galα(1,3)Gal carbohydrate epitope was not observed as Galα(1,3)Gal staining was still present in tissues from GGTA1−/− animals. This shows that, contrary to previous dogma, α1,3GT is not the only enzyme able to synthesize Galα(1,3)Gal. As iGb3 synthase (iGb3S) is a candidate glycosyltransferase, we cloned iGb3S cDNA from GGTA1−/− mouse thymus and confirmed mRNA expression in both mouse and pig tissues. The mouse iGb3S gene exhibits alternative splicing of exons that results in a markedly different cytoplasmic tail compared with the rat gene. Transfection of iGb3S cDNA resulted in high levels of cell surface Galα(1,3)Gal synthesized via the isoglobo series pathway, thus demonstrating that mouse iGb3S is an additional enzyme capable of synthesizing the xenoreactive Galα(1,3)Gal epitope. Galα(1,3)Gal synthesized by iGb3S, in contrast to α1,3GT, was resistant to down-regulation by competition with α1,2fucosyltransferase. Moreover, Galα(1,3)Gal synthesized by iGb3S was immunogenic and elicited Abs in GGTA1 −/− mice. Galα(1,3)Gal synthesized by iGb3S may affect survival of pig transplants in humans, and deletion of this gene, or modification of its product, warrants consideration.

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Section: Previous Studies Of Ggta1mentioning

confidence: 58%

The Molecular Basis for Galα(1,3)Gal Expression in Animals with a Deletion of the α1,3Galactosyltransferase Gene

Milland

Christiansen

Lazarus

et al. 2006

The Journal of Immunology

104

105

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“…The α(1, 2) fucosyltransferase gene expression has been reported to resultin a drastic suppression of the gal epitope on mouse cells due to the enzymatic competition between the α(1, 3)GT and α(1, 2) fucosyltransferase for the common acceptor substrate [23], [24]. In contrast to the mouse cells, SGC-7901, SPC-A-1 and A375 all express the blood group H antigen on the surface due to the α(1, 2) fucosyltransferase activity [18,25].…”

Section: Discussionmentioning

confidence: 99%

Adenovirus-mediated expression of pig α(1, 3) galactosyltransferase reconstructs Gal a(1, 3) Gal epitope on the surface of human tumor cells

et al. 2001

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Gal α(1, 3) Gal (gal epitope) is a carbohydrate epitope and synthesized in large amount by α(1, 3) galactosyltransferase [α(1, 3) GT] enzyme on the cells of lower mammalian animals such as pigs and mice. Human has no gal epitope due to the inactivation of α(1, 3) GT gene but produces a large amount of antibodies (anti-Gal) which recognize Gal α(1, 3) Gal structures specifically. In this study, a replication-deficient recombinant adenoviral vector Ad5sGT containing pig α(1, 3) GT cDNA was constructed and characterized. Adenoviral vector-mediated transfer of pig α(1, 3) GT gene into human tumor cells such as malignant melanoma A375, stomach cancer SGC-7901, and lung cancer SPC-A-1 was reported for the first time. Results showed that Gal epitope did not increase the sensitivity of human tumor cells to human complement-mediated lysis, although human complement activation and the binding of human IgG and IgM natural antibodies to human tumor cells were enhanced significantly after Ad5sGT transduction. Appearance of gal epitope on the human tumor cells changed the expression of cell surface carbohydrates reacting with Ulex europaeus I (UEA I) lectins, Vicia villosa agglutinin (VVA), Arachis hypogaea agglutinin (PNA), and Glycine max agglutinin (SBA) to different degrees. In addition, no effect of gal epitope on the growth in vitro of human tumor cells was observed in MTT assay.

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“…Enzymatic modifications of the carbohydrate surface of xenogeneic cells significantly reduce human antibody binding and complementmediated cytolysis (4,55,58). In addition, affinity isolation of xenoreactive human natural antibodies of the immunoglobulin M class, of which a major fraction is directed against the terminal ␣-galactose determinants on porcine endothelial cells, was used to lower the natural humoral immunologic barrier to xenotransplantation (50).…”

mentioning

confidence: 99%

Establishment and Characterization of Molecular Clones of Porcine Endogenous Retroviruses Replicating on Human Cells

Czauderna

Fischer

Boller

et al. 2000

J Virol

105

109

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The use of pig xenografts is being considered to alleviate the shortage of allogeneic organs for transplantation. In addition to the problems overcoming immunological and physiological barriers, the existence of numerous porcine microorganisms poses the risk of initiating a xenozoonosis. Recently, different classes of type C porcine endogenous retoviruses (PERV) which are infectious for human cells in vitro have been partially described. We therefore examined whether completely intact proviruses exist that produce infectious and replication-competent virions. Several proviral PERV sequences were cloned and characterized. One molecular PERV class B clone, PERV-B(43), generated infectious particles after transfection into human 293 cells. A second clone, PERV-B(33), which was highly homologous to PERV-B(43), showed a G-to-A mutation in the first start codon (Met to Ile) of the env gene, preventing this provirus from replicating. However, a genetic recombinant, PERV-B(33)/ATG, carrying a restored env start codon, became infectious and could be serially passaged on 293 cells similar to virus clone PERV-B(43). PERV protein expression was detected 24 to 48 h posttransfection (p.t.) using cross-reacting antiserum, and reverse transcriptase activity was found at 12 to 14 days p.t. The transcriptional start and stop sites as well as the splice donor and splice acceptor sites of PERV mRNA were mapped, yielding a subgenomic env transcript of 3.1 kb. PERV-B(33) and PERV-B(43) differ in the number of copies of a 39-bp segment in the U3 region of the long terminal repeat. Strategies to identify and to specifically suppress or eliminate those proviruses from the pig genome might help in the production of PERV-free animals.

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Reduction in the level of Gal(alpha1,3)Gal in transgenic mice and pigs by the expression of an alpha(1,2)fucosyltransferase.

Cited by 183 publications

References 27 publications

The Molecular Basis for Galα(1,3)Gal Expression in Animals with a Deletion of the α1,3Galactosyltransferase Gene

The Molecular Basis for Galα(1,3)Gal Expression in Animals with a Deletion of the α1,3Galactosyltransferase Gene

Adenovirus-mediated expression of pig α(1, 3) galactosyltransferase reconstructs Gal a(1, 3) Gal epitope on the surface of human tumor cells

Establishment and Characterization of Molecular Clones of Porcine Endogenous Retroviruses Replicating on Human Cells

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