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A Reutzel-Selke

Publications and source records attributed to A Reutzel-Selke.

15 recordsLinked to original sources
PubMed2006

Rat cytomegalovirus infection interferes with anti-CD4 mAb-(RIB 5/2) mediated tolerance and induces chronic allograft damage.

In order to assess the role of heterologous immunity on tolerance induction (TI) by signal 1 modification, the influence of rat cytomegalovirus infection (RCMVI) on TI by a non-depleting monoclonal anti-CD4 mAb (monoclonal antibody) (RIB 5/2) in a rat kidney transplant (KTx) model was investigated. Orthotopic rat KTx (Dark Agouty (DA)-->Lewis (LEW)) was performed after TI with RIB 5/2 [10 mg/kg body weight (BW); day -1, 0, 1, 2, 3; i.p. (intraperitoneal route)]. RCMVI (5x10E5 Plaque forming units [PFU] i.p.) was simultaneously conducted to KTx, 50 days after KTx, and 14 days before and after KTx. RIB 5/2 induced robust allograft tolerance even across the high-responder strain barrier. RCMVI broke RIB 5/2-induced tolerance regardless of the time of RCMVI but did not induce acute graft failure during the 120 days follow-up. RCMVI induced a significant chronic deterioration of allograft function (p<0.01) and enhanced morphological signs of chronic allograft damage (p<0.05). Cellular infiltrates and major histo-compatibility complex (MHC)-expression were more pronounced (p<0.05) in the infected groups. RCMVI induced not only RCMV-specific T-cell response but also enhanced the frequency of alloreactive T cells. RCMV interferes with anti-CD4 mAb-induced tolerance and leads to chronic allograft damage. The data we presented suggest a potentially important role of viral infections and their prophylaxis in clinical TI protocols.

Animals↗
PubMed2000

Mechanisms of tolerance induction in second renal allografts of a chronic rejection model.

In a previous experiment we demonstrated the induction of tolerance by the allograft itself. In this model of weak histoincompatibility, second grafts of donor origin replacing chronically rejected first renal allografts were accepted long term. Additionally grafted donor-specific hearts functioned indefinitely while adoptive transfer experiments demonstrated the development of donor-specific transferable tolerance. In the current experiment we compared intragraft gene expression of chronically rejected first and tolerant second grafts by RT-PCR. Second renal allografts of donor origin (F-344) replaced first grafts 2, 4, 8, 12, and 16 weeks after the initial engraftment. No immunosuppression was used during second engraftment. Grafts were followed by serial proteinuria; morphological and immunohistological studies (APAAP/infiltrating cells, ICAM-1, MHC II expression) and competitive RT-PCR analyses (expressed as arbitary units AU/cDNA) for relevant cells and cytokines (CD-3, IFNgamma, IL-10, and IL-4) were assessed by the end of the observation period (16 weeks). Macrophages/monocytes (ED-1+) and T-cells (CD-5 and CD-4+) infiltrated first allografts in high numbers by 12 weeks associated with strong structural signs of chronic graft rejection (ca. 30% arterio- and glomerulosclerosis, tubular atrophy and interstitial fibrosis). Cellular infiltrates in second grafts were prominent, however significantly reduced, while histological changes were minor. At cDNA levels, CD-3 transcripts were elevated in second renal allografts performed 2, 4, and 8 weeks after the initial engraftment while comparable levels were observed when second engraftment was performed after 12 and 16 weeks. Analyses of relevant cytokines demonstrated a TH1/TH2 shift independent from the time interval between first and second engraftment. These results emphasize the role of alloresponsiveness for the development of chronic graft dysfunction. Mechanisms of tolerance induction in our model are associated with a distinct alloresponsive pattern. A crucial role for regulatory T-cells is suggested.

Animals↗
PubMedDate not supplied

Quantification of donor-derived DNA in serum: a new approach of acute rejection diagnosis in a rat kidney transplantation model.

Clinical and laboratory findings of acute rejection (AR) are often late and misleading. Core needle biopsy, the most reliable diagnostic method, is usually performed late in the course of AR and is associated with several complications. Therefore noninvasive approaches to monitor the immune system for detection of early AR is one of the major aims in transplant medicine. In a fully MHC-mismatched renal allograft model in the rat, we quantified donor-derived DNA (ddDNA) in the recipient serum using real-time RT-PCR as an alternative screening procedure for the early diagnosis of acute rejection. We also investigated the influence of different immunosuppressive protocols on the levels of ddDNA. Our results show that donor-derived DNA is present in the serum of kidney allograft recipients prior to acute rejection. Animals that received a syngeneic graft and animals that received a mismatched allograft but were treated with immunosuppressive drugs did not show significant elevations of ddDNA. When steroid therapy failed to avoid acute rejection, the animals showed a delayed peak of ddDNA. In summary, the detection of ddDNA in recipient serum offers a noninvasive diagnostic approach to uncover ongoing rejection processes in the graft.

Acute Disease↗
PubMedDate not supplied

Induction of heme oxygenase-1 in the donor reduces graft immunogenicity.

There is increasing evidence that the induction of the enzyme heme oxygenase-1 (HO-1) improves both graft function and survival. Although it has been shown that HO-1 promotes graft protection, it remains unknown whether it reduces graft immunogenicity by modulating dendritic cells. In the current experiment, we investigated the impact of HO-1 induction on frequencies and trafficking of donor-derived dendritic cells (DCs). Kidneys from DA rats were transplanted into untreated Lewis recipients. Donor animals were treated with cobalt protoporphyrin (CoPP; 5 mg/kg IP) 24 hours prior to organ harvesting to induce HO-1. Controls remained untreated or received zinc protoporphyrin (ZnPP; 20 mg/kg, IP) to block HO-1 induction. Analyses of grafts, spleens, lymph nodes and blood of Lewis recipients were performed at days 1 and 3 posttransplantation. Donor-specific DCs were determined by flow cytometry using haplotype-specific mAb against RT1(ab) and mAb against OX62(+) antigens. Cell markers (CD4/CD8(+) T cells, ED1(+) monocytes, MHC class II(+) CD86(+) DC) were measured by immunohistochemical staining. T-cell alloreactivity of recipient splenocytes was measured by ELISPOT. Induction of HO-1 reduced frequencies of donor-derived DCs in the graft and recipient compartments, which was associated with reduced frequencies of CD4(+) T cells and CD8(+) T cells and alloreactivity. Expression of costimulatory molecule CD86 and MHC class II antigens were also reduced, although not significantly. Thus, induction of HO-1 reduced graft immunogenicity. These mechanisms may explain the protective effects of HO-1 induction.

Animals↗
PubMedDate not supplied

Grafts from elderly donors elicit a stronger immune response in the early period posttransplantation: a study in a rat model.

With a growing demand for transplants, grafts from older donors are increasingly used. However, altered immune responses associated with increasing donor age may influence graft survival. We dissected the effects of donor age on the immune response in an experimental model. Kidneys from young and old F-344 donors (3 and 18 months) transplanted into young Lewis recipients (3 months) were followed for 6 months. Renal function, structural changes, and immune activation were tested at serial time intervals. Splenocytes and peripheral blood mononuclear cells were examined by flow cytometry; alloantigen-specific intracellular IFN-gamma secretion was evaluated by ELISPOT. Grafts from both young and old donors survived the observation period. The ratio of structural changes (6/1 months) increased twofold in old vs young grafts. In parallel, the ratio of renal function declined by fivefold in recipients of old donor kidneys. Most interestingly, elderly grafts produced a modified immune response: the numbers of T/B cells and alloreactive T cells increased early following the transplantation of old grafts (P < .05). However, by 6 months, the amounts of T and B cells as well as alloantigen-specific immune responses were comparable in recipients of old versus young grafts. Older grafts elicit a stronger immune response during the early period posttransplantation. This process is associated with an increased immunogenicity in older grafts. Clinical immunosuppressive protocols need to consider these effects.

Aging↗