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Recipient Cells (recipient + cell)
Selected AbstractsGenetic transduction in freshwater ecosystemsFRESHWATER BIOLOGY, Issue 6 2008OLADELE A. OGUNSEITAN Summary 1. Lateral genetic exchange is a profound consequence of the co-existence of viruses (bacteriophages) and bacteria in freshwater ecosystems. Transduction is distinct from other mechanisms of genetic exchange because it is driven by potentially lethal agents external to the donor and recipient cells. Therefore, transduction is reputed to be a major driving force behind the diversity in natural populations and communities of bacteria. 2. Both generalized transduction (where every segment of the donor's genome has equal chance of being transferred to a recipient cell) and specialized transduction (where certain donor gene sequences are transferred at higher frequencies than others based on their proximity to the integration site of the transducing bacteriophage genome) have been demonstrated for various freshwater bacteria. However, these genetic exchange events occur at frequencies that vary widely, from 10,2 to 10,10 transductants per recipient, depending on the influence of various physical, chemical and biotic environmental factors on the outcome of phage,host encounters. Methodological constraints limit the interpretation of results from early studies of transduction in freshwaters because those studies introduced exogenous organisms in microcosms and excluded, to different extents, naturally occurring environmental conditions and their variability. 3. To assist the design and extrapolation of empirical observations, mathematical models including application of Group Theory are useful to estimate boundaries of the impact of transduction in generating and maintaining microbial diversity in freshwater. These theoretical excursions generate hypotheses and questions that can only be answered through refinement of current empirical estimates of transduction frequency, polarity of gene mobilization, bacteriophage host ranges, and the influence of gradients in environmental parameters that characterize freshwater ecosystems. [source] Plasmid DNA transfer in Mycobacterium smegmatis involves novel DNA rearrangements in the recipient, which can be exploited for molecular genetic studiesMOLECULAR MICROBIOLOGY, Issue 4 2004Jun Wang Summary The establishment of molecular genetic techniques is essential for development of new treatments for mycobacterial infections. To this end, we recently described a novel DNA transfer process that occurs in the model mycobacterial organism Mycobacterium smegmatis. This transfer system is most like conjugal DNA transfer in that it requires two viable parents, is DNAse resistant and occurs between distinct donor and recipient strains. Cis -acting sequences called bom, which confer transferability, are distinct from the prototypical oriT sites of conjugative plasmids, as they occur at multiple locations in the chromosome and require RecA in the recipient to mediate plasmid recircularization. Here, we show that a plasmid containing two of these bom regions can undergo several fates in the recipient cell, each of which require recipient recombination functions. The products of plasmid transfer that we observed provide further insights toward a model for DNA transfer. Furthermore, we have taken advantage of the recombination events that occur in the recipient to develop simple procedures for capturing, or replacing specific segments of the recipient chromosome. To demonstrate the potential of the system, we describe the capture and deletion of 25 kb of the M. smegmatis chromosome, and targeted-allele exchange of the recipient recB and recD genes. Using these transfer-mediated rearrangements, we demonstrate that homology with the recipient chromosome and RecB, but not RecD, are essential for DNA transfer. [source] The Epiplasm Gene EPC1 Influences Cell Shape and Cortical Pattern in Tetrahymena thermophila,THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2004NORMAN E. WILLIAMS ABSTRACT. The cortical protein Epclp is the most abundant protein in the membrane skeleton, or epiplasm, of Tetrahymena thermophila. A partial sequence of the EPC1 gene was obtained and used to obtain a knockout construct that was successful in transforming Tetrahymena thermophila cells. The results support the conclusion that Epclp influences cell shape and the fidelity of cortical development. It was further observed that this protein is transferred from plus to minus cells during conjugation, and that the imported protein is assembled into the epiplasm of the recipient cell in a discreet series of steps. [source] Horizontal transfer of an exopolymer complex from one bacterial species to anotherENVIRONMENTAL MICROBIOLOGY, Issue 4 2000D. Osterreicher-Ravid Alasan, the exocellular polymeric emulsifier produced by Acinetobacter radioresistens KA53 was shown to bind to the surface of Sphingomonas paucimobilis EPA505 and Acinetobacter calcoaceticus RAG-1. The presence of alasan on the surface of S. paucimobilis EPA505 and A. calcoaceticus RAG-1 caused a decrease in their cell-surface hydrophobicities. Binding was proportional to the concentration of recipient cells and input alasan. At the highest concentration of A. calcoaceticus RAG-1 (4 × 109 ml,1) and alasan (20 µg ml,1) tested, 75% of the alasan was cell bound. Alasan binding was measured by the loss of emulsifying activity and alasan protein and polysaccharide from the aqueous phase after incubation of alasan with the recipient cells. In addition, alasan was visualized on the surface of the recipient cells by staining with anti-alasan antibodies and rhodamine-labelled secondary antibodies. Moreover, when the alasan-producing A. radioresistens KA53 was grown together with A. calcoaceticus RAG-1, alasan was released from the producing strain and became bound to the recipient RAG-1 cells, as demonstrated by fluorescence microscopy. This horizontal transfer of exopolymers from one bacterial species to another has significant implications in natural microbial communities, coaggregation and biofilms. [source] A systematic approach to molecular quantitative determination of mixed chimaerism following allogeneic bone marrow transplantation: an analysis of its applicability in a group of patients with severe aplastic anaemiaEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2004Rocío Hassan Abstract:, Mixed chimaerism (MC) following allogeneic bone marrow transplantation (allo-BMT) is defined as the persistent cohabitation of haematopoietic cells from recipients and donors. Its kinetics, clinical implications and more efficient laboratory approaches for MC detection are the object of ongoing research in view of the possibility of developing useful markers. Here we describe a sequential analysis of chimaerism using variable number of tandem repeat (VNTR) polymerase chain reaction (PCR) followed by quantitative, fluorescent labelled, short tandem repeat (STR) PCR. A set of four, highly discriminative VNTR and four STR markers was used to assess chimaerism. Sensitivity and regression analysis indicated that this approach was reliable for routine application in a single BMT centre. We studied 12 patients with severe aplastic anaemia (SAA) who had received allo-BMT, and had been conditioned with cyclosphosphamide (Cy) with or without anti-thymocyte globulin (ATG). We found a 50% prevalence of MC in the whole group, with levels between 4% and 37% of recipient cells. A sustained stable MC pattern after BMT was characteristic of the Cy-only conditioned patients but was also recorded in one patient treated with the Cy + ATG regime who showed a sustained MC pattern over a period of 24 months post-BMT. In none of our patients, MC was associated with an increased risk of graft rejection in a median follow-up of 39.5 months. [source] Genetic transduction in freshwater ecosystemsFRESHWATER BIOLOGY, Issue 6 2008OLADELE A. OGUNSEITAN Summary 1. Lateral genetic exchange is a profound consequence of the co-existence of viruses (bacteriophages) and bacteria in freshwater ecosystems. Transduction is distinct from other mechanisms of genetic exchange because it is driven by potentially lethal agents external to the donor and recipient cells. Therefore, transduction is reputed to be a major driving force behind the diversity in natural populations and communities of bacteria. 2. Both generalized transduction (where every segment of the donor's genome has equal chance of being transferred to a recipient cell) and specialized transduction (where certain donor gene sequences are transferred at higher frequencies than others based on their proximity to the integration site of the transducing bacteriophage genome) have been demonstrated for various freshwater bacteria. However, these genetic exchange events occur at frequencies that vary widely, from 10,2 to 10,10 transductants per recipient, depending on the influence of various physical, chemical and biotic environmental factors on the outcome of phage,host encounters. Methodological constraints limit the interpretation of results from early studies of transduction in freshwaters because those studies introduced exogenous organisms in microcosms and excluded, to different extents, naturally occurring environmental conditions and their variability. 3. To assist the design and extrapolation of empirical observations, mathematical models including application of Group Theory are useful to estimate boundaries of the impact of transduction in generating and maintaining microbial diversity in freshwater. These theoretical excursions generate hypotheses and questions that can only be answered through refinement of current empirical estimates of transduction frequency, polarity of gene mobilization, bacteriophage host ranges, and the influence of gradients in environmental parameters that characterize freshwater ecosystems. [source] The rate of horizontal transmission of antibiotic resistance plasmids is increased in food preservation-stressed bacteriaJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2007M.A.S. Mc Mahon Abstract Aim: The aim of this study was to investigate the possibility that sublethal food preservation stresses (high/low temperature, osmotic and pH stress) can alter the rate of horizontal transmission of antibiotic resistance (ABR) plasmids between Escherichia coli strains and between E. coli and Salmonella serotype Typhimurium. Methods and Results: Escherichia coli donor cultures, carrying F1 plasmid R386 and Inc I1 plasmid TP307 and E. coli and Salm. Typhimurium recipient cultures were prestressed under a range of sublethal environmental conditions (high/low temperature, osmotic and pH stress). The prestressed donor and recipient cultures were then mated and the transmission rate calculated. The study found that the horizontal transmission rate of plasmids R386 and TP307 was significantly increased (P < 0·05) when prestressed donor and recipient cells are mated under conditions of environmental stress. Conclusion: The results from this study indicate that, the sublethal stresses that food pathogens encounter in modern food preservation systems increase the inter- and intra-specific horizontal transmission of selected ABR plasmids. Significance and Impact of the Study: Increased use of bacteriostatic (sublethal), rather than bacteriocidal (lethal) food preservation systems, may be contributing to the dissemination of ABR among important food borne pathogens. [source] Cell-to-cell cross-talk between mesenchymal stem cells and cardiomyocytes in co-cultureJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 5a 2008E. Y. Plotnikov Abstract The goals of the study were: (1) to explore the communication between human mesenchymal stem cells (MSC) and rat cardiac myocytes resulting in differentiation of the stem cells and, (2) to evaluate the role of mitochondria in it. Light and fluorescence microscopy as well as scanning electron microscopy revealed that after co-cultivation, cells formed intercellular contacts and transient exchange with cytosolic elements could be observed. The transport of cytosolic entity had no specific direction. Noticeably, mitochondria also could be transferred to the recipient cells in a unidirectional fashion (towards cardiomyocytes only). Transmission electron microscopy revealed significant variability in both the diameter of intercellular contacting tubes and their shape. Inside of these nanotubes mitochondria-resembling structures were identified. Moreover, after co-cultivation with cardiomyocytes, expression of human-specific myosin was revealed in MSC. Thus, we speculate that: (1) transport of intracellular elements to MSC possibly can determine the direction of their differentiation and, (2) mitochondria may be involved in the mechanism of the stem cell differentiation. It looks plausible that mitochondrial transfer to recipient cardiomyocytes may be involved in the mechanism of failed myocardium repair after stem cells transplantation. [source] Cell traffic between donor and recipient following rat limb allograftJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 1 2005Keiichi Muramatsu Abstract Although cell traffic from the graft into the recipient and from the recipient into the graft had been noticed in allogeneic organ transplantation, little is known following whole-limb allografting. This study was conducted to define cell migration between donor and recipient. Sixty-seven vascularized hind limb allotransplantations were performed in rat sex-mismatched pairs and the recipient animals were treated with FK506 immunosuppression. The ratio of donor and recipient cells was evaluated by semi-quantitative PCR using the specific primers of the Y-chromosome. Allografted limbs had no rejection episode until the final assessment. The male recipient cells were detected in female limb grafts not at 1 week but at 48 weeks after transplantation. The male donor cells were detected in the humerus and tibia in the female recipient but not in the gastrocnemius muscle and leg skin. Our results demonstrated that recipient-derived cells gradually migrated into the grafted bone, muscle and skin cells with the duration of time. Donor-derived cells migrated into the healthy bones but not into the healthy muscle and skin. Because active regeneration occurs in the grafted limb to compensate graft damage secondary to ischemia and operative intervention, recipient-derived cells may mediate a muscular and dermo-epidermal renewal. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] Arteriopathy in chronic allograft rejection in liver transplantationLIVER TRANSPLANTATION, Issue 4 2004Aya Miyagawa-Hayashino Chronic rejection is an important cause of liver allograft failures. The allograft undergoing chronic rejection shows affected large- and medium-sized muscular arteries with homing of foamy macrophages and enlargement of the intimal area. The objective of this study was to elucidate the pathogenesis of the intimal lesion that causes obliterative arteriopathy by identifying the origin of the foamy macrophages and mesenchymal cells present in the intimal area. Nine allografted livers (6 male and 3 female patients) from sex-mismatched donors undergoing chronic rejection were studied by combined staining of the macrophages or the mesenchymal cells in the intimal area with immunohistochemistry and in situ hybridization using a probe for the human Y chromosome. By using the specimens from female donor allografts transplanted to male recipients, it was found that 62 ± 11% of CD68+ foamy macrophages and 71 ± 4% of smooth muscle actin-positive mesenchymal cells in the intimal lesions and a few interstitial myofibroblasts were positive for the Y chromosome probe. This indicated that they were derived from the recipients. In conclusion, the thickening intimal lesion seen in obliterative vasculopathy in liver allografts consists of the foamy macrophages and mesenchymal cells of recipient origin. These circulating recipient cells migrated to the areas in advance of remodeling arteries. (Liver Transpl 2004;10:513,519.) [source] Immune activation is required for the induction of liver allograft tolerance: Implications for immunosuppressive therapyLIVER TRANSPLANTATION, Issue 3 2001G. Alex Bishop Liver transplants in many animal models are unusual because often they are not rejected even when transplanted across complete major histocompatibility complex barriers without immunosuppression. Their paradoxical behavior is even more obvious when the immune mechanism of acceptance is examined. Instead of acceptance resulting from a lack of immune response to the graft, the opposite occurs, and there is an unusual extensive increase in immune activation in acceptance compared with rejection. This abnormal extensive immune activation is driven by donor leukocytes transferred with the liver and results in death of the recipient cells that would normally reject the transplant. Some forms of immunosuppression inhibit this activation-associated liver transplant tolerance. The significance of these findings and possible means to design future treatment protocols for clinical transplantation that optimize management of liver transplant recipients are discussed. [source] Sequential model of phage PRD1 DNA delivery: active involvement of the viral membraneMOLECULAR MICROBIOLOGY, Issue 5 2002A. Marika Grahn Summary DNA translocation across the barriers of recipient cells is not well understood. Viral DNA delivery mechanisms offer an opportunity to obtain useful information in systems in which the process can be arrested to a number of stages. PRD1 is an icosahedral double-stranded (ds)DNA bacterial virus with an internal membrane. It is an atypical dsDNA phage, as any of the vertex spikes can be used for receptor recognition. In this report, we dissect the PRD1 DNA entry into a number of steps: (i) outer membrane (OM) penetration; (ii) peptidoglycan digestion; (iii) cytoplasmic membrane (CM) penetration; and (iv) DNA translocation. We present a model for PRD1 DNA entry proposing that the initial stage of entry is powered by the pressure build-up during DNA packaging. The viral protein P11 is shown to function as the first DNA delivery protein needed to penetrate the OM. We also report a DNA translocation machinery composed of at least three viral integral membrane proteins, P14, P18 and P32. [source] IFN-, gene therapy by intrasplenic hepatocyte transplantation: a novel strategy for reversing hepatic fibrosis in Schistosoma japonicum -infected micePARASITE IMMUNOLOGY, Issue 1 2001Lihuang Zhang Liver-targeted gene therapy using hepatocyte as recipient cells has recently been documented to be effective in treatment of numerous hepatic diseases, such as metabolic diseases and liver carcinoma. IFN-, elicits antipreliferative and antifibrogenic activity in a variety of mesenchymal cells, including hepatic satellite cells. To investigate the antifibrogenic response of liver gene therapy mediated by intrasplenic transplantation of gene-modified hepatocytes, normal mouse liver cell line BNL CL.2 cells were transfected with murine IFN-, gene (BNL.IFN-,) in vitro, and transplanted intrasplenically into Schistosoma japonicum -infected mice. The amounts and distribution of IFN-, (which inhibits collagen synthesis), TGF-, (which stimulates collagen synthesis) and extracellular matrix, including type I and III collagen, were detected. In mice infected with S. japonicum and then treated with BNL.IFN-,, an increase of IFN-, and decrease of TGF-,1 were detected at 20 weeks postinfection compared to untreated S. japonicum -infected mice. Immunohistochemical analysis showed that S. japonicum infection induced a marked increase of type I and III collagen synthesis. Whereas, 4 weeks after treatment with BNL.IFN-,, net synthesis rates of type I and III collagen were markedly decreased in the liver of infected mice. In addition, a decreased expression of TGF-,1 and its receptor TGF-,RII in the liver of BNL.IFN-,-treated mice was also observed. Moreover, the decrease in TGF-,1 and TGF-,RII protein approximately paralleled the decrease in their mRNA expression, which was detected by RNA dot blotting. The data indicate that intrasplenic transplantation of IFN-, gene-modified hepatocyte can be a candidate approach to treat hepatic fibrosis. [source] Packaging of prions into exosomes is associated with a novel pathway of PrP processing,THE JOURNAL OF PATHOLOGY, Issue 5 2007LJ Vella Abstract Prion diseases are fatal, transmissible neurodegenerative disorders associated with conversion of the host-encoded prion protein (PrPC) into an abnormal pathogenic isoform (PrPSc). Following exposure to the infectious agent (PrPSc) in acquired disease, infection is propagated in lymphoid tissues prior to neuroinvasion and spread within the central nervous system. The mechanism of prion dissemination is perplexing due to the lack of plausible PrPSc -containing mobile cells that could account for prion spread between infected and uninfected tissues. Evidence exists to demonstrate that the culture media of prion-infected neuronal cells contain PrPSc and infectivity but the nature of the infectivity remains unknown. In this study we have identified PrPC and PrPSc in association with endogenously expressing PrP neuronal cell-derived exosomes. The exosomes from our prion-infected neuronal cell line were efficient initiators of prion propagation in uninfected recipient cells and to non-neuronal cells. Moreover, our neuronal cell line was susceptible to infection by non-neuronal cell-derived exosome PrPSc. Importantly, these exosomes produced prion disease when inoculated into mice. Exosome-associated PrP is packaged via a novel processing pathway that involves the N-terminal modification of PrP and selection of distinct PrP glycoforms for incorporation into these vesicles. These data extend our understanding of the relationship between PrP and exosomes by showing that exosomes can establish infection in both neighbouring and distant cell types and highlight the potential contribution of differentially processed forms of PrP in disease distribution. These data suggest that exosomes represent a potent pool of prion infectivity and provide a mechanism for studying prion spread and PrP processing in cells endogenously expressing PrP. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] REVIEW ARTICLE: The Role of Placental Exosomes in ReproductionAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010Lucia Mincheva-Nilsson Citation Mincheva-Nilsson L, Baranov V. The Role of Placental Exosomes in Reproduction. Am J Reprod Immunol 2010 Cell communication comprises cell,cell contact, soluble mediators and intercellular nanotubes. There is, however, another cell,cell communication by released membrane-bound microvesicles that convey cell,cell contact ,by proxy' transporting signals/packages of information from donor to recipient cells locally and/or at a distance. The nanosized exosomes comprise a specialized type of microvesicles generated within multivesicular bodies (MVB) and released upon MVB fusion with the plasma membrane. Exosomes are produced by a variety of immune, epithelial and tumor cells. Upon contact, exosomes transfer molecules that can render new properties and/or reprogram their recipient cells. Recently, it was discovered that the syncytiotrophoblast constitutively and throughout the pregnancy secretes exosomes. The placenta-derived exosomes are immunosuppressive and carry proteins and RNA molecules that in a redundant way influence a number of mechanisms and promote the fetal allograft survival. In this review, we summarize the current knowledge on the nature of placenta-derived exosomes and discuss their role in pregnancy. [source] Death from Metastatic Donor-Derived Ovarian Cancer in a Male Kidney Transplant RecipientAMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2009G. S. Lipshutz Posttransplant malignancy developing in an allograft is an uncommon complication of organ transplantation. The tumor may represent malignant transformation of donor or recipient cells that were previously normal, metastatic malignancy of recipient origin or malignancy transmitted from organ donor to recipient. Establishing the origin of the malignancy is critical to treatment algorithms. It is generally believed allograft removal and immunosuppression withdrawal will lead to resolution of transmitted malignancies in cases where the renal allograft is the origin. We report a male patient who developed metastatic ovarian malignancy secondary to donor transmission. [source] Effect of carbon source addition on toluene biodegradation by an Escherichia coli DH5, transconjugant harboring the TOL plasmidBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2010Kaoru Ikuma Abstract Horizontal gene transfer (HGT) of plasmids is a naturally occurring phenomenon which could be manipulated for bioremediation applications. Specifically, HGT may prove useful to enhance bioremediation through genetic bioaugmentation. However, because the transfer of a plasmid between donor and recipient cells does not always result in useful functional phenotypes, the conditions under which HGT events result in enhanced degradative capabilities must first be elucidated. The objective of this study was to determine if the addition of alternate carbon substrates could improve toluene degradation in Escherichia coli DH5, transconjugants. The addition of glucose (0.5,5,g/L) and Luria,Bertani (LB) broth (10,100%) resulted in enhanced toluene degradation. On average, the toluene degradation rate increased 14.1 (±2.1)-fold in the presence of glucose while the maximum increase was 18.4 (±1.7)-fold in the presence of 25% LB broth. Gene expression of xyl genes was upregulated in the presence of glucose but not LB broth, which implies different inducing mechanisms by the two types of alternate carbon source. The increased toluene degradation by the addition of glucose or LB broth was persistent over the short-term, suggesting the pulse amendment of an alternative carbon source may be helpful in bioremediation. While the effects of recipient genome GC content and other conditions must still be examined, our results suggest that changes in environmental conditions such as alternate substrate availability may significantly improve the functionality of the transferred phenotypes in HGT and therefore may be an important parameter for genetic bioaugmentation optimization. Biotechnol. Bioeng. 2010;107: 269,277. © 2010 Wiley Periodicals, Inc. [source] A UGT2B17-positive donor is a risk factor for higher transplant-related mortality and lower survival after bone marrow transplantationBRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2005Seitaro Terakura Summary We recently identified a human minor histocompatibility (H) antigen, encoded by UDP glycosyltransferase 2 family, polypeptide B17 (UGT2B17), whose immunogenicity results from differential expression in donor and recipient cells as a consequence of a homozygous deletion of the UGT2B17 gene. UGT2B17 is highly expressed in the liver and colon, which are major targets for graft- versus -host disease (GVHD). To assess the significance of homozygous UGT2B17 gene deletion in allogeneic haematopoietic stem cell transplantation (HSCT), we analysed DNA from 435 stem cell transplant recipients with a haematological malignancy and their human leucocyte antigen-identical unrelated bone marrow donors using sequence-specific primer polymerase chain reaction. Homozygous deletion of the UGT2B17 gene was observed in 85% of normal donors and in 82% of patients. The analysis showed no significant association between UGT2B17 mismatch in the GVHD direction and the incidence of acute GVHD, chronic GVHD, relapse, or survival. However, the use of a UGT2B17-positive donor was an independent risk factor for higher transplant-related mortality and lower survival after transplantation. UGT2B17 is a metabolic enzyme for hormones, drugs, and potentially toxic exogenous compounds and is expressed in subsets of haematopoietic cells. Thus, the enzyme function of UGT2B17 in donor cells may affect the outcome of allogeneic HSCT. [source] Detection of recipient's cells in liver graft using antibodies to mismatched HLA class I antigensLIVER TRANSPLANTATION, Issue 11 2004Alberto Grassi Engraftment by recipient's (R) cells has been already demonstrated in gender mismatched liver grafts using fluorescence in situ hybridization (FISH), with contrasting results concerning epithelial cells. Mismatch for human leukocyte antigen (HLA) class I (HLA-I) is quite common in patients with orthotopic liver transplantation (OLT). We thus aimed to assess whether monoclonal antibodies (MoAbs), currently employed in the HLA typing process, could be used to study the dynamics of R cells in liver grafts. A total of 50 frozen liver biopsies from 37 patients receiving a HLA mismatch liver were tested. Biopsies were obtained from 3 days to more than 360 days after OLT. Frozen sections of graft biopsies were stained using an immunoperoxidase technique with the proper MoAbs. In selected cases, a double immunofluorescence was also performed. Circulating R blood cells and sinusoidal cells were occasionally observed in liver biopsies obtained within 10 days after OLT and were commonly detected after 1 month. The number of sinusoidal cells continued to increase up to 6 months, as shown on serial biopsies. On the whole, R blood cells and R sinusoidal cells were detected in 86% and 82% of the biopsies, respectively. R hepatocytes and biliary cells were detected after 40 and 60 days after OLT, respectively, in 14% (hepatocytes), 8% (bile ducts), and 12% (proliferating bile ducts) of the biopsies. R hepatocytes presented as single cells or groups of few cells; their number was lower than 1% and apparently did not increase with time after OLT. In conclusion, it is possible to detect R cells in liver graft using MoAbs to specific mismatched HLA-I alleles. R sinusoidal cells start to appear after 10 days and are commonly observed after 1 month; bile duct cells and hepatocytes appear later and their number does not increase with time. Engraftment by R epithelial cells seems to be less important than previously reported. (Liver Transpl 2004;10:1406,1414.) [source] | |||||||||||||||||||||||||