Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A single intravenous injection of freshly heparinized blood from a donor-specific blood transfusion (DST) seven days before transplantation significantly prolongs the subsequent survival of hepatic allografts from ACI(RT1a) to LEW(RT1(1)) rats. We used W3/25 (anti-CD4) and OX22 (anti-CD45RC: an isoform of leukocyte-common antigen [CD45R]) monoclonal antibodies to investigate the cellular identity of hepatic allograft infiltrates following transplantation. The number of CD4+ and CD45RC+ cells in untreated allografts increased equally over time by day seven. However, in DST-treated hepatic allografts, CD4+ and CD45RC+ cells also increased over time by day 14, but the increment in the number of CD4+ cells was significantly greater than that in CD45RC+ cells. While the number of CD4+ cells remained persistently elevated in the hepatic allografts of rats pretreated with DST, they did not initiate rejection. Fluorescence-activated cell sorter (FACS) analysis revealed that the accumulated CD4+ T cells could be divided into two subsets, CD45RC- CD4+ and CD45RC+ CD4+ T cells, and that the ratio of CD45RC- CD4+/CD45RC+ CD4+ T cells in the hepatic allografts of recipients pretreated with DST was significantly greater than that in untreated allografts. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis demonstrated that CD45RC- CD4+ T cells expressed interleukin (IL)-4 and IL-10 messenger RNA (mRNA), but not IL-2 and interferon gamma (IFN-gamma). The pattern of messenger RNA expression in hepatic allograft infiltrates from animals pretreated with DST provides compelling evidence for the selective in vivo preservation of T-helper (Th2)-specific cytokines in the rat system. Our studies show that CD45RC leukocyte-common antigen expression can define different populations of hepatic infiltrating CD4+ T cells. A persistent infiltration of CD45RC- CD4+ T cells, Th2-like effector cells, is characteristic of hepatic allografts with a prolonged survival in DST-pretreated rats.
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PMID:Persistent infiltration of CD45RC- CD4+ T cells, Th2-like effector cells, in prolonging hepatic allografts in rats pretreated with a donor-specific blood transfusion. 909 12

Allospecific CTL can function as cellular effectors of solid organ graft rejection; however, the specific mechanisms of cell damage remain undetermined. In this study we examined the role of CD8+ T cells in apoptosis and rejection of small intestinal allografts. ACI rat intestinal grafts transplanted into Lewis rat recipients showed apoptosis of epithelial crypt cells on day 3 posttransplant as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling staining. By day 7 numerous apoptotic crypt cells were detected in allografts, but were rarely observed in FK506-treated allograft recipients, isografts, or native intestine of allograft recipients. To further investigate the mechanism of rejection, recipient rats were depleted of CD8+ cells by treatment with OX-8 mAbs the day before and the day after transplantation of rat small intestinal allografts. Depletion of CD8+ cells from allograft recipients did not alter the tempo or the histologic features of rejection compared with those in the control (IgG-treated) group. Moreover, there was no difference in the number of apoptotic crypt epithelial cells in the grafts of control and CD8-depleted rats. Reverse transcriptase-PCR analyses determined there were similar levels of transcripts for Fas, Fas ligand, perforin, and granzyme B in control and CD8-depleted allograft recipients. By Western blot it was determined that the levels of Fas ligand protein were increased in the CD8-depleted group compared with those in control and FK506-treated allograft recipients. These data suggest that CD8 cells are not required for tissue injury or apoptotic cell death in small intestine allograft rejection.
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PMID:CD8+ cells are not necessary for allograft rejection or the induction of apoptosis in an experimental model of small intestinal transplantation. 955 67

It has previously been shown that a single intravenous injection of freshly heparinized donor-specific blood transfusion (DST) before transplantation significantly prolongs the survival of fully allogeneic ACI (RT1a)-to-LEW(RT1(1)) rat hepatic allografts. Additionally, we have shown that pretreatment of LEW rats with PVG.r1 blood, which shares only the RT1.A major histocompatibility complex (MHC) region with ACI, significantly prolongs the survival of ACI hepatic allografts. In this study, we report the cellular identity of hepatic allograft leukocyte infiltrates following transplantation. Fluorescence-activated cell sorting (FACS) analysis revealed that CD4+ T cells infiltrating liver allografts could be divided into two subsets, CD45RC- CD4+ and CD45RC+ CD4+ T cells, and that the ratio of CD45RC- CD4+/CD45RC+ CD4+ T cells was significantly higher in hepatic allografts of recipients pretreated with DST or PVG.r1 blood as compared to untreated allografts. Further, CD8+ T cells that accumulated in the liver grafts could be similarly divided into two subsets, and the ratio of CD45RC- CD8+/CD45RC+ CD8+ T cells was also significantly higher in hepatic allografts of recipients pretreated with DST or PVG.r1 blood. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that CD45RC- CD4+ T cells harvested from hepatic allografts pretreated with PVG.r1 blood expressed interleukin-4 (IL-4) and interleukin-10 (IL-10), but not interleukin-2 (IL-2) or interferon-gamma (IFN-gamma). In contrast, CD45RC- CD8+ T cells from hepatic allografts pretreated with PVG.r1 blood expressed IL-4, IL-10, and IFN-lambda, but not IL-2. These results indicate that the CD45RC leukocyte common antigen could be used to differentiate CD4+ and CD8+ T cells following pretreatment with DST or PVG.r1 blood. Persistent infiltration of CD45RC- CD4+ and CD45RC- CD8+ T cells, capable of secreting Th2-type cytokines may prevent allograft rejection by causing immunologic unresponsiveness.
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PMID:Infiltrating CD45RC- T cells are associated with immunologic unresponsiveness induced by donor class I major histocompatibility complex antigens in rats. 969 11