IgY antiporcine endothelial cell antibodies effectively block human antiporcine xenoantibody binding

The purpose of this study was to estimate the possibilities of an acellular matrix using a modified acellularization protocol, which circumvents immunological, microbiological, and physiological barriers. We treated porcine subclavian arteries with various reagents to construct acellular grafts. Afterwards, these grafts were interposed in a mongrel dogs' abdominal aorta. Six dogs underwent interposition with fresh porcine grafts (control group), and seven had interposed acellular grafts (acellular group). The control and acellular group dogs were sacrificed at 1, 3, 5 (n=2 in each group) and 12 months (n=1 in acellular group) after the operation. Histopathological examinations were then performed, to assess the degree to which re-endothelialization, inflammation, thrombus formation, and calcification occurred. The entire acellular group, but none of the control group, exhibited re-endothelialization. The degrees to which inflammation, thrombosis, and calcification occurred were found to be lower in the acellular group. We also discovered many smooth muscle cells in the medial layer of the xenograft that had been implanted in the dog sacrificed 12 months after the operation. These results suggest that the construction of xenografts using our modified acellularization protocol may offer acceptable outcomes as a vascular xenograft.

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“…Complete eradication of exogenous viral infection and removal of endogenous retrovirus, however, has been reported (26). …”

Section: Discussionmentioning

confidence: 99%

Modified Acellularization for Successful Vascular Xenotransplantation

Sohn

Choi

et al. 2007

J Korean Med Sci

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“…Immunological staining has shown that in pig tissue there are several antigens with different Galα1‐terminated epitopes 26 , 27 ). Xenoreactive antibodies may thus exhibit broad specificities by reacting with Galα1‐3Gal determinants being either terminally located or present as core structures 28 .…”

Section: Discussionmentioning

confidence: 99%

Binding of Griffonia simplicifolia 1 isolectin B4 (GS1 B4) to α‐galactose antigens

Kirkeby¹,

Moe²

2001

Immunol Cell Biol

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SummaryGlycoconjugates with terminal Galα1-3Galβ1-4GlcNAc sequences (α-galactosyl epitopes, natural xenoreactive antigens) are present on various tissues in pigs and are recognized by human anti-αgalactosyl (αGal) antibodies 1 . Hence xenotransplantation (pig-to-human) would trigger immune reactions involving complement activation and lead to the hyperactute rejection of the graft. Xenoreactive antigens are often studied by using the lectin Griffonia simplicifolia 1 isolectin B4 (GS1 B4), which shows high affinity to galactose. We here estimate the specificity of GS1 B4 for detecting various galactosyl epitopes by measuring lectin binding to neoglycoproteins, thyroglobulin and pig skeletal muscle. Enzyme linked lectin assays confirmed that GS1 B4 was highly specific to α-galactosylated neoglycoproteins while the lectin did not detect a β-galactosylated ligand. The length of the sugar chains influenced the lectin-carbohydrate interaction. A monosaccharide linked to serum albumin showed higher lectin affinity than did neoglycoproteins with di-and tri-α-galactosyl epitopes. When the carbohydrate was extended, as in the xenoreactive pentasaccharide (Galα1-3Galβ1-4GlcNAcβ1-3Galβ1-4Glc), the carbohydratelectin interaction was meagre. Not only the terminal, but also the subterminal sugar affected the lectin binding because the GS1 B4 affinity to Galα1-3Gal was much stronger than to Galα1-3GalNAc. In bovine and porcine thyroglobulin most αGal epitopes appear to be cryptic, but are unmasked by a heat denaturation. In pig skeletal muscle there was lectin reaction not only in the muscle capillaries, but also in the connective tissue and intracellularly in muscle fibres. In Western blots of isolated proteins from pig muscle at least three bands were strongly stained after incubation with lectin.

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“…One possible way is to block the epitope with anti‐αGal IgY, made in the chicken, because IgY does not activate mammalian complement or bind to mammalian Fc receptors. Previously we have shown that IgY anti‐αGal pretreatment of porcine endothelial cells blocks human XNA binding, complement activation and antibody‐dependent cell‐mediated cellular cytotoxicity (ADCC)‐type effector functions 12 …”

Section: Discussionmentioning

confidence: 99%

“…Anti‐αGal IgY was prepared by immunizing chickens with αGal epitope conjugated to ovalbumin or keyhole limpet haemocyanin, isolating the IgY fraction from egg yolks, and affinity purifying the anti‐αGal fraction using Synsorb‐90 beads as previously described 12 . The portion of IgY which did not bind to the αGal epitope on the Synsorb‐90 matrix was termed the IgY flow‐through (FT‐IgY).…”

Section: Methodsmentioning

confidence: 99%

“…The immunohistochemical procedures were similar to those previously described 12 . Briefly, heart, lung, liver, kidney, spleen and pancreas tissues were sectioned at a thickness of 8 µm, placed on slides and incubated with biotinylated‐GSI‐B4 lectin followed by fluorescinated–avidin reagent to detect αGal epitopes, and incubated with fluorescinated anti‐IgY, anti‐mouse IgG or anti‐mouse IgM reagents to detect the respective immunoglobulins.…”

Section: Methodsmentioning

confidence: 99%

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Distribution of, and immune response to, chicken anti‐αGal immunoglobulin Y antibodies in wild‐type and αGal knockout mice

Walsh

Anderson

Ivancic³

et al. 2000

Immunology

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SUMMARYChicken antibodies (immunoglobulin Y; IgY) to the aGal epitope (galactose a-1,3-galactose) bind to aGal antigens of mouse and porcine tissues and endothelial cells in vitro and block human antiaGal antibody binding, complement activation and antibody-dependent cell-mediated lysis mechanisms. The activities and toxicity of anti-aGal IgY have not been tested in vivo. In this study, we tested the effects of multiple injections of af®nity-puri®ed anti-aGal IgY (AP-IgY) in both wild-type (WT) and a-1,3-galactosyltransferase knockout (Gal KO) mice. WT and Gal KO mice were injected once, twice, three, or four times intravenously (i.v.) with AP-IgY and killed at 1 hr or 24 hr. Mice displayed no toxicity to four injections of AP-IgY. Heart, lung, liver, kidney, spleen and pancreatic tissue were evaluated using immunohistochemical techniques for the presence of the aGal epitope using the GSI-B4 lectin, and for bound IgY, as well as mouse IgM and IgG. The binding of AP-IgY antibodies to the endothelium of WT mouse tissues was essentially identical to the pattern of binding of the GSI-B4 lectin after injection of WT mice and death at 1 hr. WT mice killed 24 hr after i.v. injection of AP-IgY showed little remaining bound IgY in their endothelia, indicating that IgY is cleared over that time period. We also evaluated the blood drawn at the time of death for the presence of anti-aGal IgY, anti-IgY IgM and anti-IgY IgG by enzyme-linked immunosorbent assay. Anti-aGal IgY was almost undetectable in WT mouse sera at all injection and killing times. In contrast, Gal KO mouse sera showed increasing anti-aGal IgY levels until 24 hr after the fourth injection, when anti-aGal IgY levels were almost undetectable. Anti-IgY IgM and IgG levels in WT and Gal KO mouse sera showed a typical increase in anti-IgY IgM 24 hr after the second injection (3 days after the ®rst injection) and an increase in anti-IgY IgG 24 hr after the third injection (5 days after the ®rst injection). These results show that IgY binds to aGal epitopes in the WT mice and is cleared sometime over a 24-hr time period and that IgY is an expected immunogen in mice eliciting a rather typical anti-IgY IgM and IgG response.

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IgY antiporcine endothelial cell antibodies effectively block human antiporcine xenoantibody binding

Cited by 39 publications

References 49 publications

Modified Acellularization for Successful Vascular Xenotransplantation

Modified Acellularization for Successful Vascular Xenotransplantation

Binding of Griffonia simplicifolia 1 isolectin B4 (GS1 B4) to α‐galactose antigens

Distribution of, and immune response to, chicken anti‐αGal immunoglobulin Y antibodies in wild‐type and αGal knockout mice

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