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Shuji Miyagawa

Publications and source records attributed to Shuji Miyagawa.

At least 19 recordsLinked to original sources
PubMed2006

Features of a newly cloned pig C1 esterase inhibitor.

The pig cDNA encoding C1 esterase inhibitor (C1-INH) was isolated and the homology of the sequence was compared with that from other animals. The structure of pig C1-INH contains a two disulfide bridge pattern identical to the human C1-INH. In the amino acid sequence of the first Cys-91 to the C-terminal end, the pigC1-INH has a 76.2% homology with the human protein, and the sequence of the reactive site is close to the human. A surface-bound form of pig and human C1-INH, pC1-INH-PI and hC1-INH, respectively, were next constructed. Stable Chinese hamster ovarian tumor (CHO) cell lines and pig endothelial cell (PEC) lines expressing these C1-INH-PI were prepared by transfection. The basic function and the species specificity of pCI-INH were then investigated using these transfectants. pC1-INH and hC1-INH have almost the same suppressive effect on pig, human, dog and rabbit sera in complement-dependent cell lysis, indicating little species specificity.

Amino Acid Sequence↗
PubMed2006

Involvement of position-147 for HLA-E expression.

HLA-E functions as an inhibitory signaling molecule of natural killer (NK) cell-mediated cytolysis. However, the cell surface expression of HLA-E molecules is quite restricted because of the limited repertoire of binding peptide sequences, such as signal peptides of other HLA molecules, especially on xenogeneic cells. In this study, we successfully determined that position-147 is an important amino acid position for cell surface expression by producing point substitutions. For further studies concerning transplantation therapy, the point substitution, Ser147Cys, that resulted in a single atom change, oxygen to sulfur, designated as HLA-Ev(147), led to a much higher expression on the human and pig cell surface and a greater inhibitory function against human NK cells than wild type HLA-E in an in vitro model system of pig to human xenotransplantation. Consequently, HLA-Ev(147) might be a promising alternative gene tool for future transplantation therapy such as xenotransplantation.

Amino Acid Sequence↗
PubMed2006

Molecular cloning of pigGnT-I and I.2: an application to xenotransplantation.

Xenotransplantation is one of the most attractive solutions for the current worldwide shortage of organs. The knocking out of alpha1,3-galactosyltransferase in pigs resulted in a drastic reduction in xenoantigenicity. However, more recent studies indicate that other xeno-antigens, so-called non-Gal antigens, will also need to be downregulated. In this study, pig N-acetylglucosaminyltransferase I (GnT-I), a key enzyme that initiates the biosynthesis of hybrid- and complex-type N-linked sugar chains, was isolated and the pigGnT-I.2 specific for the O-linked sugar chain was also isolated. Point mutants, pigGnT-I(123) and pigGnT-I(320), were subsequently constructed. While pigGnT-I(123) shows an indistinct dominant negative effect for endogenous GnT-I in pig cells, pigGnT-I(320) had a drastic effect. In addition, in the case of pig cell transfectants with pigGnT-I(320), cell surface carbohydrate structures were significantly altered and its antigenicity to human serum was reduced. Consequently, pigGnT-I(320) appears to be potentially useful in xenotransplantation by remodeling the carbohydrate structures on pig cells.

Amino Acid Sequence↗
PubMed2006

A novel strategy for preventing PERV transmission to human cells by remodeling the viral envelope glycoprotein.

BACKGROUND: Porcine endogenous retrovirus (PERV) released from pig cells is a main problem associated with clinical xenotransplantation. In a previous study, we demonstrated that the high mannose type of N-glycan of the envelope glycoprotein is closely related to PERV infectivity with respect to human cells. In this study, we addressed the effects of reducing the high mannose type of N-glycan on PERV infectivity. METHODS: Pig endothelial cells (PEC) were transduced with the LacZ gene by a pseudotype infection to produce PEC(Z). The PEC(Z)s were then further infected with PERV subtype B (PERV-B) to produce PEC(Z)/PB. The PEC(Z)/PBs were next transfected with the alpha 1,2 mannosidase Ib (Man Ib), N-acetylglucosaminyltransferase I (GnT-I) or alpha-mannosidase II (Man II) gene in order to reduce the levels of high mannose type of N-glycan. HEK293 cells were inoculated with the PERV in each of the culture supernatants. The inoculated cells were histochemically stained and the LacZ-positive cells were counted. RESULTS: In experiment I, PERV transmission from the PEC(Z)/PB with GnT-I or Man II to HEK 293 cells was significantly reduced in comparison with control PEC(Z)/PB, while the PEC(Z)/PB with Man Ib was not. However, in experiment II, PERV transmission from the PEC(Z)/PB with ManIb to HEK 293 cells was also significantly reduced in comparison with control PEC(Z)/PB. CONCLUSION: The transfection of these genes to pig cells is effective in reducing the susceptibility of human cells to PERV infection. The results suggest that this represents a potentially useful strategy for further decreasing the likelihood of PERV infections.

Animals↗
PubMed2006

Effect of tandem forms of DAF(CD55) on complement-mediated xenogeneic cell lysis.

BACKGROUND: It is difficult to produce a transgenic animal with high expression of decay-accelerating factor (CD55: DAF) or other molecules. The purpose of this study was to assess the effect of tandem forms of DAF on a xenogeneic cell membrane against human complement. METHODS: cDNAs of the delta-Short Consensus Repeat (SCR) 1-DAF, the double-DAF, the triple-DAF, and the tetra-DAF with a FLAG-tag were established. Chinese hamster ovary (CHO) cell lines and a pig endothelial cell (PEC) line expressing these molecules were established. The amelioration of complement-mediated lysis by the transfectant molecules on these cells was examined. The CHO cell transfectants were also incubated with normal human serum, and the amount of C3 deposited was determined by FACS analysis. RESULTS: Stable CHO cells and PEC transfectants, in which each molecule was clearly expressed, and Western blots showed that each band corresponded to the expected molecular weight. The extent of amelioration of complement-mediated lysis by these four molecules was then examined. A clear tendency was found, as follows: The higher the tandem number of DAF, the greater was the effect on cytotoxicity. Additional experiments focusing on triple-DAF and tetra-DAF did not indicate any significant difference in complement-mediated lysis. Consistent with the complement-regulatory ability, the inhibitory effect of the deposition of C3 fragments by these molecules was closely related to the degree of amelioration. CONCLUSION: These data indicate that tandem DAF, especially a triple-DAF, is a very effective form for protecting against complement activation.

Animals↗
PubMed2006

A study of the xenoantigenicity of neonatal porcine islet-like cell clusters (NPCC) and the efficiency of adenovirus-mediated DAF (CD55) expression.

BACKGROUND: The pig pancreas is considered to be the most suitable source of islets for xenotransplantation in patients with type I diabetes. The objective of this study was to assess the antigenicity of neonatal porcine islet-like cell clusters (NPCC), including the Galalpha1-3Galbeta1-4GlcNAc-R (alpha-Gal) and Hanganutziu-Deicher (H-D) antigens, and the pathway involved in human complement activation. The efficiency of expression of human decay-accelerating factor (DAF: CD55) on NPCC by adenoviral transduction was also examined, and the functional capacity of DAF was also estimated. METHODS: The deposition of human natural antibodies, immunoglobulin (Ig)G and IgM, and the expression of alpha-Gal and H-D antigens on NPCC were investigated by FACS analysis. The downregulation in the antigenicity to human natural antibodies, including the alpha-Gal and H-D antigens on NPCC by treatment with tunicamycin, PDMP and neuraminidase were also examined. In addition, complement-mediated islet lysis was examined using factor D-deficient and C1-deficient sera. An adenovirus encoding DAF under the control of the cytomegalovirus promoter, Ad.pCMV-DAF, was then constructed, and used for transducing NPCC. The amelioration of complement-dependent cytotoxicity of the NPCC by the transduced DAF was assessed as an in vitro hyperacute rejection model of a pig to human xenograft. RESULTS: The NPCC clearly expressed the alpha-Gal epitope, and the human natural antibodies, IgG and IgM, and the anti-H-D antibody also reacted with the NPCC. Treatment of NPCC with tunicamycin led to a drastic reduction in the extent of deposition of IgG, indicating the importance of N-linked sugars on the islets, presumably related to alpha-Gal expression on N-linked sugars. Neuraminidase treatment indicated the presence of, not only the H-D antigen, but also other sialic acid antigens which reacted with the human natural antibody, especially IgG. The complement deposition of factor B on NPCC was clear, and the alternative pathway-mediated NPCC killing accounted for approximately 30% of that by the total complement pathway. On the other hand, approximately 90% of the NPCC could be transduced to express DAF by the adenovector, Ad.pCMV-DAF. The expressed DAF showed an approximately 50-62% suppression in complement-dependent NPCC lysis. CONCLUSION: The origin of the antigenicity of NPCC is mainly N-linked sugars including alpha-Gal and sialic acid antigens, and NPCC expressed the transduced molecule in high efficiency by the adenovector.

Adenoviridae↗
PubMed2005

Choice of the adequate detection time for the accurate evaluation of the efficiency of siRNA-induced gene silencing.

RNA interference (RNAi) mediated by small interfering RNA (siRNA) has become a popular tool of examining the function of various genes. However, many studies have failed to identify any inhibitory effect of the siRNAs on the expression of the target gene, even though the siRNA being tested had been designed sequence-specifically. In order to determine if this failure is due to the incorrect choice of observation time rather than that of the target site of the gene of interest, this study examined the RNAi efficiency of a vector-driven siRNA targeting two different reporter proteins, EGFP and d2EGFP, whose targeted sequences were identical but the half-lives within the cells differed remarkably from each other (>24h versus 2h), during the time course after transfection. The EGFP expression levels in both cells were reduced in time-dependent manner but the reduction patterns were quite different from each other. The RNAi efficiency varied among the different observation time points and the time required for the maximum RNAi efficiency was proportional to the half-life of the target protein. Stable knocked down cell lines for EGFP expression were then established and the reduced EGFP expression levels in these cell lines were retained for a long period. These results suggest that the choice of an adequate observation time or the establishment of stable knocked down cells by antibiotic selection might be required for making an accurate evaluation of the RNAi effect on the target protein possessing a long half-life.

Animals↗
PubMed2005

Production of alpha 1,3-galactosyltransferase gene knockout pigs expressing both human decay-accelerating factor and N-acetylglucosaminyltransferase III.

Heterozygous alpha 1,3-galactosyltransferase (GT) gene knockout pigs were produced with transgenic pig fetal cells expressing both human decay-accelerating factor (hDAF) and N-acetylglucosaminyltransferase III (GnT-III). In this study, we assessed the gene targeting efficiency in the transgenic pig fetal cells derived from different fetal tissues such as brain, skin, heart, and liver, or fetal carcass. Targeted cell colonies were selected by hygromycin B. The GT-knockout colonies (KO colonies) were obtained equally from the cells derived from all tissues except liver. Staining with five antibodies against intermediate filaments, all examined KO cell lines stained positive for vimentin with the exception of a colony that stained positive for both vimentin and glial fibrillary acidic protein simultaneously. This is the first study to produce KO cells from the astrocytes. Some of these KO cell lines were used for nuclear transfer (NT) to obtain KO pig fetuses. Fourteen fetuses were obtained from two recipients of the embryo transfer and eight of them had normal ploidy. The cells from the KO pig fetuses were also used for NT to produce cloned KO pigs. Two healthy clone pigs were born. These pigs were determined to have a heterozygous knockout GT gene and the two transgenes. The cells collected from the KO pigs were shown to have similar expression levels of hDAF and GnT-III compared to their original transgenic pigs and less than a half levels of the alphaGal epitopes existed in wild-type pig cells.

Animals↗
PubMed2005

Prevention of PERV infections in pig to human xenotransplantation by the RNA interference silences gene.

The possibility of preventing the transmission of porcine endogenous retrovirus (PERV) to human cells using short interfering RNAs (siRNA) was investigated. The siRNA for the p30 of PERV gag region was cloned into pSUPER, the polymerase-III H1-RNA gene promoter. A green fluorescence protein (GFP) was also cloned into pSUPER to establish pSXGH. Pig endothelial cells (PEC) were transduced with the LacZ gene by pseudotype infection, and infected with PERV subtype B, resulting in the formation of PEC(LacZ)/PB. The PEC(LacZ)/PB was next transfected with pSXGH-siRNA. The expression of siRNA was provisionally checked by determining the level of expression of GFP. Culture supernatants of infected cells were then inoculated into HEK293 cells. The siRNA clearly destroyed the PERV infectivity of PEC(LacZ)/PB in both transient cell lines and stable clones. Moreover, the decreased levels of mRNA and gag protein were evidenced in the stable clones by real-time PCR and Western blotting, respectively. The final goal of our study was to establish a transgenic pig expressing the siRNA for PERV. The results suggest that siRNA represents a novel approach for controlling PERV infections in clinical xenotransplantation.

Animals↗
PubMed2005

Survival of adult islet grafts from transgenic pigs with N-acetylglucosaminyltransferase-III (GnT-III) in cynomolgus monkeys.

BACKGROUND: Because of a severe shortage of human donor pancreases, pig islets are considered to be an attractive donor source. Our previous in vitro study revealed that adult pig islets have strong non-Galalpha1-3Galbeta1-4GlcNAc-R (alpha-Gal) antigenicity, including the Hanganutziu-Deicher (H-D) antigen, especially in N-linked sugars. In this study, the issue of whether islets from N-acetylglucosaminyltransferase-III (GnT-III) transgenic pigs can prolong their survival in cynomolgus monkeys was examined. METHODS: Adult pig islets were isolated from transgenic pigs with GnT-III and wild-type genes. GnT-III enzyme activity in pig islets was measured by high performance liquid chromatography (HPLC). The antigenicity of the islets to human natural antibodies was examined by flow cytometry. Pig islets were transplanted under the kidney capsule of streptozotocin-induced diabetic monkeys. After transplantation, blood samples were obtained and plasma insulin levels were monitored on a daily basis. RESULTS: While GnT-III was barely expressed in wild-type islets, it was expressed at high levels in islets from transgenic pigs, and xenoantigenicity was significantly reduced. There was a trend for islets isolated from GnT-III-transgenic pigs to survive longer than those from wild-type pigs in cynomolgus monkeys (wild type: 1, 1, and 3 days; GnT-III: 1, >3, 4 and 5 days). Humoral and histological studies indicated up-regulated anti-pig islet antibodies and a relatively high deposition in islet grafts from wild-type pigs, respectively. CONCLUSION: A reduction in xenoantigenicity by GnT-III may have prolonged the survival of porcine islets, suggesting the importance of non-alpha-Gal and non-H-D antigens, as they relate to N-linked sugars in the early rejection of porcine islets in the monkey. This approach may be useful in the clinical xenotransplantation of islets in the future.

Animals↗
PubMed2005

Complete loss of Ndel1 results in neuronal migration defects and early embryonic lethality.

Regulation of cytoplasmic dynein and microtubule dynamics is crucial for both mitotic cell division and neuronal migration. NDEL1 was identified as a protein interacting with LIS1, the protein product of a gene mutated in the lissencephaly. To elucidate NDEL1 function in vivo, we generated null and hypomorphic alleles of Ndel1 in mice by targeted gene disruption. Ndel1(-/-) mice were embryonic lethal at the peri-implantation stage like null mutants of Lis1 and cytoplasmic dynein heavy chain. In addition, Ndel1(-/-) blastocysts failed to grow in culture and exhibited a cell proliferation defect in inner cell mass. Although Ndel1(+/-) mice displayed no obvious phenotypes, further reduction of NDEL1 by making null/hypomorph compound heterozygotes (Ndel1(cko/-)) resulted in histological defects consistent with mild neuronal migration defects. Double Lis1(cko/+)-Ndel1(+/-) mice or Lis1(+/-)-Ndel1(+/-) mice displayed more severe neuronal migration defects than Lis1(cko/+)-Ndel1(+/)(+) mice or Lis1(+/-)-Ndel1(+/+) mice, respectively. We demonstrated distinct abnormalities in microtubule organization and similar defects in the distribution of beta-COP-positive vesicles (to assess dynein function) between Ndel1 or Lis1-null MEFs, as well as similar neuronal migration defects in Ndel1- or Lis1-null granule cells. Rescue of these defects in mouse embryonic fibroblasts and granule cells by overexpressing LIS1, NDEL1, or NDE1 suggest that NDEL1, LIS1, and NDE1 act in a common pathway to regulate dynein but each has distinct roles in the regulation of microtubule organization and neuronal migration.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2004

Delta-short consensus repeat 4-decay accelerating factor (DAF: CD55) inhibits complement-mediated cytolysis but not NK cell-mediated cytolysis.

NK cells play a critical role in the rejection of xenografts. In this study, we report on an investigation of the effect of complement regulatory protein, a decay accelerating factor (DAF: CD55), in particular, on NK cell-mediated cytolysis. Amelioration of human NK cell-mediated pig endothelial cell (PEC) and pig fibroblast cell lyses by various deletion mutants and point substitutions of DAF was tested, and compared with their complement regulatory function. Although wild-type DAF and the delta-short consensus repeat (SCR) 1-DAF showed clear inhibition of both complement-mediated and NK-mediated PEC lyses, delta-SCR2-DAF and delta-SCR3-DAF failed to suppress either process. However, delta-SCR4-DAF showed a clear complement regulatory effect, but had no effect on NK cells. Conversely, the point substitution of DAF (L147 x F148 to SS and KKK(125-127) to TTT) was half down-regulated in complement inhibitory function, but the inhibition of NK-mediated PEC lysis remained unchanged. Other complement regulatory proteins, such as the cell membrane-bound form factor H, fH-PI, and C1-inactivator, C1-INH-PI, and CD59 were also assessed, but no suppressive effect on NK cell-mediated PEC lysis was found. These data suggest, for DAF to function on NK cells, SCR2-4 is required but no relation to its complement regulatory function exists.

Amino Acid Substitution↗
PubMed2004

Human cytomegalovirus UL18 alleviated human NK-mediated swine endothelial cell lysis.

Human cytomegalovirus UL18, a MHC class I homologue, is known to serve as a natural killer cell (NK) decoy and to ligate NK inhibitory receptors to prevent lysis of an infected target cell. To explore whether the cell surface expression of UL18 represents a potential immune suppressive approach to evade NK-mediated cytotoxicity in the prevention of xenograft rejection, we examined the effect of the UL18 expression in vitro upon human NK-mediated cytotoxicity against swine endothelial cells (SECs). UL18 expression on SECs by a retroviral vector (PLNCX2) significantly suppressed NK-mediated SEC lysis by approximately 25-100%. The protective effect of UL18 could be mediated through ILT-2 inhibitory receptor on NKs. Additionally, the interaction between UL18 and NKs resulted in the significant reduction of IFN-gamma production. This study demonstrates that UL18 can serve as an effective tool for the evasion of NK-mediated cytotoxicity and for the inhibition of IFN-gamma production during xenograft rejection.

Animals↗
PubMed2004

Only the light chain is sufficient for the serine protease function of the membrane bound form of factor I on a xeno-surface.

The cell membrane-bound forms of whole factor I (fI-PI), the light chain of the serine protease (SP) domain (SP-PI), and the light chain plus the COOH-terminal 45 amino acid (AA) of the heavy chain (SP+45-PI) were constructed. Chinese hamster ovary (CHO) cells, expressing these molecules were established by transfection of cDNA and confirmed by flow cytometry. Amelioration of complement-mediated cell lysis and complement fragment deposition on the cell surface by the transfectant molecules was tested in each CHO cell by means of a lactate dehydrogenase (LDH) assay and flow cytometry, respectively. A highly expressed fI-PI blocked human complement-mediated cell lysis by approximately 84% of the cells. CHO cell transfectants with SP-PI also showed a clear inhibition in cell lysis by human serum, whereas CHO cell transfectants with SP+45-PI showed no inhibition. In addition, fI-PI and SP-PI, but not SP+45-PI, suppressed C5b-9 deposition on CHO cell surface. These data indicate that the last 45 amino acid of the heavy chain, including a disulfide bridge area, did not participate in the serin protease function of factor I. The results suggest that SP-PI has potential for use in clinical xenotransplantation.

Animals↗
PubMed2004

Skin graft of double transgenic pigs of N-acetylglucosaminyltransferase III (GnT-III) and DAF (CD55) genes survived in cynomolgus monkey for 31 days.

BACKGROUND: Our previous study reported that cynomolgus monkey did not hyperacutely reject a skin xenograft from a N-acetylglucosaminyltransferase III (GnT-III) transgenic pig. In the present study, we reported on the survival time of skin xenografts in GnT-III, DAF (CD55), and double (D/G) transgenic pigs, and the effect of FK506 thereon. MATERIAL AND METHODS: Skin from GnT-III, DAF and D/G transgenic pigs were transplanted to cynomolgus monkeys. Under general anesthesia, full thickness skin defects (1.5 x 1.5 cm each) were made on the back of the monkey. Pig abdominal skin, obtained using an electric dermatome, was cut into pieces and transplanted onto the monkey wounds and fixed. In addition, skins of GnT-III and D/G pigs were also transplanted to cynomolgus monkeys that had been treated intramuscularly with FK506 at a dose of 0.5 mg/kg/day for 14 days after transplantation. Grafts were observed and photographed each day and skin graft biopsies were done on days 3, 5, 7, 10, 11, 14, 21, 28 and 31 after transplantation. Graft rejection was assessed histologically, based on our previous criteria for skin allografts. RESULTS: Even in the immuno-suppressive drug free condition, skin xenografts of GnT-III, DAF and D/G transgenic pigs were not hyperacutely rejected in early phase after transplantation by the cynomolgus monkey. The pattern of these xenograft rejections was histologically similar to those for rat allograft rejections. Most of the GnT-III, DAF and D/G pig skin grafts remained nearly intact up to day 5, but slight lymphocyte infiltration was noted on day 7 (grade 1). On day 9, while the GnT-III skin showed moderate lymphocyte and eosinophilic infiltration, the DAF and D/G pig skin grafts showed complete epidermal separation (grade 3). On the other hand, in the case of cynomolgus monkeys treated with FK506, the GnT-III skin showed complete epidermal separation (grade 3) on day 21. In addition, one of the D/G skin graft was intact on day 21 and moderate lymphocyte infiltration and intraepidermal blister formation (grade 1) was finally seen on day 31. CONCLUSION: Our data show the possibility that both the DAF and GnT-III double transgenic pig skin xenografts can be used in place of human skin allografts in cases of severe burns.

Animals↗
PubMed2004

Cloning of the transgenic pigs expressing human decay accelerating factor and N-acetylglucosaminyltransferase III.

The present paper describes production of cloned pigs from fibroblast cells of transgenic pigs expressing human decay accelerating factor (DAF, CD55) and N-acetylglucosaminyltransferase III (GnT-III) that remodels sugar-chain biosynthesis. Two nuclear transfer protocols were used: a two-step activation (TA) method and a delayed activation (DA) method. Enucleated in vitro-matured oocytes and donor cells were electrically fused in a calcium-containing medium by TA method or in a calcium-free medium by DA method, followed by electrical activation 1-1.5 h later, respectively. In vitro blastocyst formation rates of nuclear transferred embryos reconstructed by TA and DA method were 8% and 14%, respectively. As a result of embryo transfer of the reconstructed embryos made by each method into recipient pigs, both gave rise to cloned piglets. These cloned pigs expressed transgene as much as their nuclear donor cells. In conclusions, (1) pig cloning can be carried out by TA or DA nuclear transfer methods, (2) expression of transgenes can be maintained to cloned pigs from the nuclear donor cells derived from transgenic animals.

Animals↗
PubMed2004

A study of the xenoantigenicity of adult pig islets cells.

BACKGROUND: The pig pancreas is considered to be the most suitable source of islets for xenotransplantation into patients with type I diabetes. The purpose of this study was to assess the antigenicity of pig islets, including the Galalpha1-3Galbeta1-4GlcNAc-R (the alpha-Gal) and Hanganutziu-Deicher (H-D) antigens, and the pathway involved in human complement activation. METHODS: The expression of alpha-Gal on islets from adult pigs was investigated by immunohistochemical staining and flowcytometric analysis. The alpha1,3 galactosyltransferase (alpha1,3GT) activity of islets was determined by high-performance liquid chromatography. Antigenicity to human natural antibodies, including the H-D antigen of pig islets was next examined by treatment of pig islets with tunicamycin, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) and/or neuraminidase. In addition, complement-mediated islets lysis was examined using factor D-deficient and C1-deficient sera. RESULTS: Adult pig islets expressed negligible amounts of alpha-Gal epitope, and alpha1,3GT activity was also undetectable. However, human natural antibodies, immunoglobulin G and M, and the anti H-D antibody react to the adult islet. Treatment of pig islets with tunicamycin, but not PDMP, led to a drastic reduction in antigenicity to human serum, indicating the importance of N-linked sugars on the islets. Neuraminidase treatment indicated the presence of, not only the H-D antigen, but also other sialic acid antigens that reacted with the human natural antibody. The complement deposition of C4, C3 and factor B on islets was demonstrated. The alternative pathway-mediated pig islet killing accounted for approximately 30% of that by the total complement pathway. CONCLUSION: The origin of antigenicity of pig islets is mainly N-linked sugars including sialic acid antigens, but not the alpha-Gal, and pig islets can be injured by both the classical and the alternative complement pathway in human serum.

ABO Blood-Group System↗