Successful active immunization using a hepatitis B virus vaccination protocol for a recipient with hepatitis B core antibody-positive liver graft

INTRODUCTION

Donor shortages occasionally necessitate the use of hepatic allografts from hepatitis B core antibody-positive (HBcAb+) donors, with an attendant risk of post-transplantation hepatitis B virus (HBV) infection. The aim of the present study was to develop and evaluate a protocol of active immunization for prevention of post-transplantation de novo HBV infection in patients receiving liver grafts from HBcAb+ donors.

PATIENTS AND METHODS

Ten patients who had received HBcAb+ liver grafts at Shinshu University Hospital between October 1996 and December 2012 were enrolled. All the recipients were negative for HBV serological tests, and HBV-DNA. Hepatitis B immunoglobulin (HBIG) was given routinely in the peritransplantation and post-transplantation periods, without antiviral drugs. Subcutaneous vaccination with recombinant HBV was given at a dosage of 20 μg in adults and 5 μg in children concomitant with HBIG until acquisition of active immunization. The timing to start HBV vaccination was dependent on the condition of the patient.

RESULTS

The median follow-up period after liver transplantation was 140 months, and the median period after transplantation until the start of vaccination was 7.0 months. Nine patients (90%) acquired active immunity after a median number of 4 (range, 2-13) vaccinations (hepatitis B surface antibody >300 mIU/mL for 1 year, or >100 mIU/mL thereafter), and did not require HBIG administration thereafter. None had any side effects of HBV vaccination or developed hepatitis B infection during the study period. Four fast responders who achieved antibody high titers by active immunization within 9 months received pretransplantation vaccinations, whereas 5 slow responders did not.

CONCLUSIONS

Our vaccination protocol provides a new effective strategy for prevention of de novo hepatitis B infection after liver transplantation in recipients with HBcAb+ liver grafts. Pretransplantation HBV vaccination was helpful for the post-transplantation vaccine response.

Generation of a felinized swine endothelial cell line by expression of feline decay-accelerating factor

Embryonic stem cell research has facilitated the generation of many cell types for the production of tissues and organs for both humans and companion animals. Because ≥30% of pet cats suffer from chronic kidney disease (CKD), xenotransplantation between pigs and cats has been studied. For a successful pig to cat xenotransplant, the immune reaction must be overcome, especially hyperacute rejection. In this study, we isolated the gene for feline decay-accelerating factor (fDAF), an inhibitor of complement proteins, and transfected a swine endothelial cell line with fDAF to "felinize" the pig cells. These fDAF-expressing cells were resistant to feline serum containing anti-pig antibodies, suggesting that felinized pig cells were resistant to hyperacute rejection. Our results suggest that a "felinized" pig kidney can be generated for the treatment of CKD in cats in the future.

Monocytic suppressor cells derived from peripheral blood suppress xenogenic natural killer cell lysis

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) were initially found to contribute to immunosuppression in tumor patients and have recently been recognized as a subset of innate immune cells that are capable of regulating adaptive immunity. A variety of innate immune stimuli, such as lipopolysaccharide, act as a double-edged sword, inducing both the maturation of dendritic cells and the expansion of MDSCs.

METHODS

We isolated MDSCs from peripheral blood mononuclear cells (PBMCs) and examined the suppressive effect of MDSCs against xenocytotoxicity mediated by YT cells, a natural killer-like cell line, with the use of the lactate dehydrogenase assay method.

RESULTS

Although primed MDSCs induced no significant suppression in YT cell-mediated cytotoxicity, activated MDSCs significantly suppressed the xenogenic cytotoxicity.

CONCLUSIONS

These findings indicate that MDSCs have a great deal of potential as a therapeutic strategy for dealing with xenograft rejection. Further investigations of the underlying mechanisms will facilitate the development of this therapeutic strategy.

31 PRODUCTION EFFICIENCY OF GENE KNOCKOUT PIGS USING GENOME EDITING AND SOMATIC CELL CLONING

Genome editing technologies have been used as a powerful strategy for the generation of genetically modified pigs. We previously developed genetically modified clone pigs with organogenesis-disabled phenotypes, as well as pigs exhibiting diseases with similar features to those of humans. Here, we report the production efficiency of various gene knockout cloned pigs from somatic cells that were genetically modified using zinc finger nucleases (ZFN) or transcription activator-like effector nucleases (TALEN). The ZFN- or TALEN-encoding mRNAs, which targeted 7 autosomal or X-linked genes, were introduced into porcine fetal fibroblast cells using electroporation. Clonal cell populations carrying induced mutations were selected after limiting dilution. The targeted portion of the genes was amplified using PCR, followed by sequencing and mutation analysis. Among the collected knockout cell colonies, cells showing good proliferation and morphology were selected and used for somatic cell nuclear transfer (SCNT). In vitro-matured oocytes were obtained from porcine cumulus-oocyte complexes cultured in NCSU23-based medium and were used to obtain recipient oocytes for SCNT after enucleation. SCNT was performed as reported previously (Matsunari et al. 2008). The cloned embryos were cultured for 7 days in porcine zygote medium (PZM)-5 to assess their developmental ability. Cloned embryos were transplanted into the oviduct or uterus of oestrus-synchronized recipient gilts to evaluate their competence to develop to fetuses or piglets. Cloned embryos reconstructed with 7 types of knockout cells showed equal development to blastocysts compared with those derived from the wild-type cells (54.5–83.3% v. 60.7%). Our data (Table 1) demonstrated that the reconstructed embryos derived from knockout cells could efficiently give rise to cloned offspring regardless of the type of genome editing methodology (i.e. ZFN or TALEN). Table 1.Production efficiency of gene knockout cloned pigs using genome editing This study was supported by JST, ERATO, the Nakauchi Stem Cell and Organ Regeneration Project, JST, CREST, Meiji University International Institute for Bio-Resource Research (MUIIBR), and JSPS KAKENHI Grant Number 26870630.

Anti-porcine abumin IgG antibodies are elicited in diabetic non-human primate recipients after intraportal porcine islet transplantation (TRAN3P.890)

Xenoreactive antibody responses were investigated in non-human primate (NHP) recipients after porcine islet transplantation (pITx). The levels of anti-αGal and anti-nonGal IgG Abs in serial sera of the recipients were measured by ELISA and flow cytometry using GalT-KO porcine endothelial cells (PECs), respectively. We detected an elicited anti-nonGal IgG response in some sera of the recipients. Through a series of work including EP of protein extracts from GalT-KO PECs, Western blot and MALDI-TOF/TOF mass spectrometry, the putative antigen was identified as bovine albumin. The sera positive of anti-nonGal Ab revealed strong IgG binding to both bovine and porcine albumin, but no binding to human albumin by ELISA. When anti-human, bovine and porcine albumin Abs were measured in pre- and post-pITx sera of 29 NHP recipient, the frequencies of the development of anti-porcine albumin IgG Abs were significantly different according to the types of immunosuppression (IS) regimen: 5/5 (100%) receiving conventional IS regimen, 2/2 (100%) receiving anti-CD154 and sirolimus and 2/21 (9.5%) receiving CD40-CD40L blockade, sirolimus and either anti-ICAM-1 or ATG (P<0.0001 vs. other groups, χ2 test). The anti-bovine albumin IgG was also detected in the sera of 6 (67%) from 9 recipients positive for elicited anti-porcine albumin IgG. These experiments indicate that anti-porcine/bovine albumin Abs are elicited in NHP recipients after porcine ITx, which can be prevented by an adequate IS.

Disruption of the temporally regulated cloaca endodermal β-catenin signaling causes anorectal malformations

The cloaca is temporally formed and eventually divided by the urorectal septum (URS) during urogenital and anorectal organ development. Although congenital malformations, such as anorectal malformations (ARMs), are frequently observed during this process, the underlying pathogenic mechanisms remain unclear. β-Catenin is a critical component of canonical Wnt signaling and is essential for the regulation of cell differentiation and morphogenesis during embryogenesis. The expression of β-catenin is observed in endodermal epithelia, including URS epithelia. We modulated the β-catenin gene conditionally in endodermal epithelia by utilizing tamoxifen-inducible Cre driver line (Shh^CreERT2). Both β-catenin loss- and gain-of-function (LOF and GOF) mutants displayed abnormal clefts in the perineal region and hypoplastic elongation of the URS. The mutants also displayed reduced cell proliferation in the URS mesenchyme. In addition, the β-catenin GOF mutants displayed reduced apoptosis and subsequently increased apoptosis in the URS epithelium. This instability possibly resulted in reduced expression levels of differentiation markers, such as keratin 1 and filaggrin, in the perineal epithelia. The expression of bone morphogenetic protein (Bmp) genes, such as Bmp4 and Bmp7, was also ectopically induced in the epithelia of the URS in the β-catenin GOF mutants. The expression of the Msx2 gene and phosphorylated-Smad1/5/8, possible readouts of Bmp signaling, was also increased in the mutants. Moreover, we introduced an additional mutation for a Bmp receptor gene: BmprIA. The Shh^CreERT2/+; β-catenin^flox(ex3)/+; BmprIA^flox/− mutants displayed partial restoration of URS elongation compared with the β-catenin GOF mutants. These results indicate that some ARM phenotypes in the β-catenin GOF mutants were caused by abnormal Bmp signaling. The current analysis revealed the close relation of endodermal β-catenin signaling to the ARM phenotypes. These results are considered to shed light on the pathogenic mechanisms of human ARMs.

Proposal to modify the International Union Against Cancer staging system for perihilar cholangiocarcinomas

BACKGROUND

The International Union Against Cancer (UICC) staging system for perihilar cholangiocarcinoma changed in 2009. The aim of this study was to validate and optimize the UICC system for these tumours.

METHODS

This retrospective study was conducted in eight Japanese hospitals between 2001 and 2010. Perihilar cholangiocarcinoma was defined as a cholangiocarcinoma that involves the hilar bile duct, independent of the presence or absence of a liver mass component. The stratification ability of the UICC tumour node metastasis (TNM) system was compared with that of a modified system.

RESULTS

Of 1352 patients, 35.9, 44.8 and 12.6 per cent had Bismuth type IV tumours, nodal metastasis (N1) and distant metastasis (M1) respectively. T4 tumours (43.2 per cent) and stage IVA (T4 Nany M0; 36.3 per cent) disease were most common. Survival was not significantly different between patients with T3 versus T4 tumours (P = 0.284). Survival for patients with stage IVA disease was comparable to that for patients with stage IIIB tumours (T1-3 N1 M0) (P = 0.426). Vascular invasion, pancreatic invasion, positive margin, N1 and M1 status were identified as independent predictors of survival. When Bismuth type IV tumours were removed from the T4 determinants and N1 tumours grouped together, the modified grouping had a higher linear trend χ2 and likelihood ratio χ2 compared with the original system (245.6 versus 170.3 respectively and 255.8 versus 209.3 respectively).

CONCLUSION

The present data suggest that minimal modification with removal of Bismuth type IV tumours from the T4 determinants and bundling of N1 disease may enhance the prognostic ability of the UICC system. However, this requires validation on an independent data set.

The suppression of inflammatory macrophage-mediated cytotoxicity and proinflammatory cytokine production by transgenic expression of HLA-E

BACKGROUND

Macrophages participate in xenogenic rejection and represent a major biological obstacle to successful xenotransplantation. The signal inhibitory regulatory protein α (SIRPα) receptor was reported to be a negative regulator of macrophage phagocytic activity via interaction with CD47, its ligand. Because a majority of human macrophages express the inhibitory receptor CD94/NKG2A, which binds specifically to the human leukocyte antigen (HLA)-E and contains immunoreceptor tyrosine-based inhibition motifs (ITIMs), the inhibitory function of HLA class I molecules, HLA-E, on macrophage-mediated cytolysis was examined. The suppressive effect against proinflammatory cytokine production by macrophages was also examined.

METHODS

Complementary DNA (cDNA) of HLA-E, and CD47 were prepared and transfected into swine endothelial cells (SEC). The expression of the modified genes was evaluated by flow cytometry and macrophage-mediated cytolysis was assessed using in vitro generated macrophages.

RESULTS

Transgenic expression of HLA-E significantly suppressed the macrophage-mediated cytotoxicity. HLA-E transgenic expression demonstrated a significant suppression equivalent to CD47 transgenic expression. Furthermore, transgenic HLA-E suppressed the production of pro-inflammatory cytokines by inflammatory macrophages.

CONCLUSIONS

These results indicate that generating transgenic HLA-E pigs might protect porcine grafts from, not only NK cytotoxicity, but also macrophage-mediated cytotoxicity.

A cloning of cytidine monophospho-N-acetylneuraminic acid hydroxylase from porcine endothelial cells

INTRODUCTION

The Hanganutziu-Deicher (H-D) antigen with terminal N-glycolyl neuraminic acid-(NeuGc) is widely distributed in mammalian species including monkeys and apes, but is not found in humans and birds. After the knock out of α1, 3galactosyltransfease, the H-D antigen became a major antigen of the "non-Gal antigen." The expression of NeuGc is controlled by the activity of cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH). In this study, molecular cloning of pig CMAH was performed, as the first step in producing H-D knockout pigs.

METHODS

A pig endothelial cell line, MYP30, was used. The DNA sequence of pig CMAH was queried in dbEST (NCBI) using the BLAST program to search for cDNA fragments of pig CMAH, based on an alignment analysis of the mouse CMAH sequence. A polymerase chain reaction experiment was performed and candidate cDNA clones were isolated. To obtain the 5'-end and 3'-end of the open reading frame sequence, a 5'-full RACE Core Set and 3'-full RACE Core Set were used.

RESULTS

We cloned and characterized the pig CMAH gene. The ATG is located in exon 4, which corresponds to the mouse gene, and the stop codon is in exon 17. In the case of the 5' site of the gene, exon 3 was identified but exons 1 and 2 are still being investigated. On the other hand, exon 18 was newly identified in the 3' site of the gene.

CONCLUSION

The results represent useful information for future clinical xenotransplantation studies.

Trial using pig cells with the H-D antigen knocked down

PURPOSE

This report describes an attempt to reduce the expression level of Hanganutziu-Deicher (H-D) antigens by small interfering RNA (siRNA) for pig cytidine monophospho-N-acetylneuraminic acid hydroxylase (pCMAH).

METHODS

A pig endothelial cell (PEC) line, and PEC and fibroblasts from an α1,3galactosyltransferase knockout (GalT-KO) piglet were used. Real-time PCR was used to evaluate the degradation of mRNA by siRNA. The H-D antigen was stained, and then the cells were incubated with human serum for the FACS analysis. The extent of lysis in human serum was next calculated using an LDH assay.

RESULTS

Suppression of the mRNA of pCMAH by each siRNA was first determined. The mixture of siRNAs for pCMAH reduced the expressions of the H-D antigen on the PEC and fibroblasts to a considerable extent. The further reduction in the xenoantigenicity for human serum of the GalT-KO cells was then confirmed. In addition, the PEC line showed a significant downregulation in complement-dependent cytotoxicity by the siRNAs, thus indicating that the anti-H-D antigen in human serum is capable of causing lysis of the pig cells.

CONCLUSION

pCMAH silencing by siRNA reduced the expression of the H-D antigen and its antigenicity, thus confirming that the H-D antigen is one of the major non-Gal antigens in this situation.

Temporary auxiliary partial orthotopic liver transplantation using a small graft for familial amyloid polyneuropathy

Donor shortage is a major issue in liver transplantation. We have successfully performed temporary auxiliary partial orthotopic liver transplantation (APOLT) using a small volume graft procured from a living donor for recipients with familial amyloid polyneuropathy (FAP). The aim of this study was to evaluate this procedure by comparing it with standard living donor liver transplantation (LDLT). We compared 13 recipients undergoing this procedure with 23 recipients undergoing a standard LDLT for the treatment of FAP. The estimated donor graft volume and the graft volume/recipient's standard liver volume ratio were significantly smaller in the temporary APOLT group than in the standard LDLT group. Postoperative complications were comparable, although the hospital stay was longer in the temporary APOLT group. All the patients safely underwent a remnant native liver resection about 2 months after their first operation in the temporary APOLT group. No symptoms related to FAP developed before the remnant liver resection, and no significant differences in graft and patient survival were observed between the two groups. We successfully performed temporary APOLT using a small volume liver graft without postoperative liver failure for FAP. Temporary APOLT for FAP might be a useful alternative procedure for expanding the donor pool for LDLT.