Keisuke Hayamizu

Monocyte-derived dendritic cell precursors facilitate tolerance to heart allografts after total lymphoid irradiation

BACKGROUND Previous studies have shown that posttransplant total lymphoid irradiation, anti-thymocyte globulin, and an intravenous donor blood cell infusion induce tolerance to ACI heart allografts in Lewis rat hosts. METHODS In the current study, fresh ACI monocytes and dendritic cell precursors, derived from short-term culture of the latter cells in granulocyte macrophage colony-stimulating factor, were tested for their capacity to prolong heart allograft survival in this model. RESULTS The experimental results show that significant prolongation of graft survival was achieved after injection of the fresh donor monocytes or 2-day or 6-day cultured cells. The 2-day cultured cells were most effective, and more than 60% of hosts maintained graft survival for more than 160 days. Ten-day cultured cells and fresh splenic dendritic cells failed to prolong graft survival. Studies of cell surface markers showed that the 2-day cultured cells had up-regulated class II major histocompatibility complex and CD80, but not CD86 molecules. On the other hand, the 10-day cultured cells and splenic dendritic cells showed intense expression of all three markers. The latter cells stimulated vigorous proliferative and cell-mediated lympholysis responses in the mixed leukocyte reaction, but the fresh and 2-day cultured cells were weak stimulators. CONCLUSION The intravenous injection of donor dendritic cell precursors derived from blood monocytes facilitates long-term acceptance of heart allografts.

Cyclosporine facilitates chimeric and inhibits nonchimeric tolerance after posttransplant total lymphoid irradiation.

BACKGROUND Previous studies showed that Lewis rats given posttransplant total lymphoid irradiation, antithymocyte globulin, and a single infusion of ACI peripheral blood or bone marrow cells develop tolerance to ACI heart allografts. METHODS To determine the effects of cyclosporine on these tolerance induction protocols, groups of Lewis hosts, given either ACI blood or marrow infusions, were given a 60-day course of daily cyclosporine immediately after the cell infusion. RESULTS Cyclosporine treatment was associated with uniform graft rejection in the groups given an ACI blood transfusion, and was associated with uniform graft acceptance in the groups given an ACI bone marrow infusion. Studies of donor-type T and B cell chimerism in the host blood showed that cyclosporine facilitated chimerism in the hosts given ACI bone marrow cells, and stable chimerism over a 300-day observation period was predicted by detectable chimerism by day 30. None of the hosts given ACI blood cells developed chimerism. CONCLUSION Cyclosporine facilitated long-term graft acceptance in a tolerization protocol that induced mixed chimerism, but prevented long-term graft acceptance in a tolerization protocol that did not induce chimerism.

Comparison of chimeric acid and non-chimeric tolerance using posttransplant total lymphoid irradiation: cytokine expression and chronic rejection.

Background. Previous studies showed that an intravenous infusion of donor blood cells facilitates tolerance to ACI heart allografts in Lewis rat hosts given posttransplant total lymphoid irradiation (TLI) and anti-thymocyte globulin (ATG). The object of the current study was to compare tolerance induction using donor cells that do or do not induce chimerism. Methods. Normal peripheral blood mononuclear cells (PBMC), granulocyte colony-stimulating factor (G-CSF)-mobilized PBMC, and bone marrow (BM) cells from ACI donors were tested for their capacity to prolong ACI heart allograft survival in Lewis hosts. Chimerism, anti-donor cell reactivity, and cytokine gene expression in grafts were determined. Results. Intravenous injections of equal numbers of all three donor cells markedly prolonged graft survival (median: >164 to >175 days) as compared to uninjected controls (median: 53 days). Chimerism among T and B cells in the blood was determined by immunofluorescent staining in hosts bearing long-term (>150 days) grafts. Although no chimerism was detected in hosts given normal or G-CSF-mobilized PBMC, chimerism was detected at variable levels in all hosts given BM cells. Vigorous anti-donor reactivity in the mixed leukocyte reaction was present only in non-chimeric hosts. Long-term grafts from hosts given normal ACI PBMC developed chronic rejection, but those from hosts given ACI BM cells did not. The latter hosts showed the lowest levels of intragraft cytokine mRNA. Conclusions. Chimeric tolerance is more robust than non-chimeric tolerance in the model of posttransplant TLI, ATG, and donor cell infusion, and is associated with less chronic rejection.

Regulation of T helper type-1 immunity in hapten-induced colitis by host pretreatment with granulocyte colony-stimulating factor☆ ☆

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is an immunoregulatory drug whose effects include modulation of antigen-presentation. We investigated the potential ameliorative effect of pretreatment with rhG-CSF in a hapten-induced colitis animal model. Sprague-Dawley rats were given rhG-CSF (125 microg/kg subcutaneously twice a day for 5 days) before a colonic instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Consequent colonic damage was evaluated pathologically, and cytokine mRNA expression levels in macroscopically inflamed sites were measured by real-time quantitative reverse transcription-polymerase chain reaction. Pretreatment with rhG-CSF remarkably attenuated both the loss of body weight and colonic wall thickening due to progressive transmural inflammation. In the control, treatment with TNBS led to a statistically significant (p < 0.05) upregulation of IFN-gamma mRNA expression in the inflammatory sites measured at post-treatment day 7. In the experimental group, pretreatment with rhG-CSF abrogated transcription of IFN-gamma (p < 0.05), but was not, however, associated with an upregulation of IL-4 or the regulatory cytokines TGF-beta and IL-10. Furthermore, transcription of IL-12p35 (a rate-limiting factor for the production of IL-12) was significantly (p < 0.05) downregulated by rhG-CSF at 24h post-TNBS instillation, whereas IL-12p40 was not affected. Pretreatment with rhG-CSF drastically attenuated the degree of TNBS-induced colitis through selective downregulation of Th1-associated cytokines.

Prolongation of liver allograft survival after interleukin-10 gene transduction 24-48 hours before donation.

BACKGROUND Interleukin- (IL) 10 may be a potent regulator for controlling of allograft rejection. A single administration of IL-10 is not effective for controlling graft rejection. Gene transfer is an attractive vehicle for prolonging the expression of short-lived proteins. METHODS Donor or recipient livers were transduced with 1 x 10(10) p.f.u. of replication-deficient adenovirus vectors harboring human IL-10 cDNA (AdCMVhIL-10) via the ileocecal vein before or after rat orthotopic liver transplantation. RESULTS DA allografts given AdCMVhIL-10 24-48 hr before donation survived for more than 56 days in Lewis recipients, although DA allografts given the adenovirus vector 7 days or 6 hr before, and 3 days after transplantation were rejected within 30 days in recipients. Serum levels of human IL-10 in gene-transferred rats were maximum from day 2 to 7. The serum level of human IL-10 then decreased gradually, and human IL-10 was not detected by ELISA 30 days after gene-transduction. In gene-transduced long-term surviving liver allografts, IL-10 was expressed, and the expression of IL-4 was also up-regulated on posttransplant day 3, despite the expression of Th1 cytokines (IL-2 and interferon-gamma), although in rejected liver allografts, IL-2 and interferon-gamma were expressed without expression of IL-4 and IL-10. CONCLUSIONS The prolongation of survival of IL-10 cDNA transferred liver allografts might be due to inhibition of the early phase of alloimmune-response by over expression of IL-10, despite the expression of IL-2 and interferon-gamma.

Donor blood monocytes but not T or B cells facilitate long-term allograft survival after total lymphoid irradiation.

BACKGROUND Previous studies showed that a combination of posttransplant total lymphoid irradiation (TLI), rabbit antithymocyte globulin (ATG), and a single donor blood transfusion induced tolerance to ACI heart allografts in Lewis rats. All three modalities were required to achieve tolerance. The objective of the current study was to determine the subset(s) of cells in the donor blood that facilitated long-term allograft survival. METHODS Lewis hosts received TLI, ATG, and donor cell infusion after heart transplantation. Graft survival, mixed leukocyte reaction (MLR), and intragraft cytokine mRNA were studied. RESULTS The intravenous injection of 25 x 10(6) ACI peripheral blood mononuclear cells (PBMC) significantly prolonged graft survival as compared with that of Lewis hosts given TLI and ATG alone. Injection of highly enriched blood T cells or splenic B cells adjusted for the number contained in 25 x 10(6) PBMC failed to induce significant graft prolongation. Unexpectedly, depletion of monocytes (CD11b+ cells) from PBMC resulted in the loss of graft prolongation activity. Enriched populations of monocytes obtained by plastic adherence were more efficient in prolonging graft survival than PBMC on a per cell basis. Hosts with long-term grafts (>100-day survival) showed evidence of immune deviation, because the MLR to ACI stimulator cells was vigorous, but secretion of interferon-gamma in the MLR was markedly reduced. In situ hybridization studies of long-term grafts showed markedly reduced levels of interferon-gamma mRNA as compared with rejecting grafts. CONCLUSION Infusion of donor monocytes facilitated graft prolongation via immune deviation.

Mechanisms of tolerance to rat heart allografts using posttransplant TLI : Changes in cytokine expression

Lewis rats were rendered tolerant to ACI heart allografts using a regimen of posttransplant total lymphoid irradiation (TLI), rabbit antithymocyte or antilymphocyte globulin (RATG or RALG), and a single donor blood transfusion. All three treatment modalities were required to induce tolerance. The mechanism of the maintenance of tolerance was investigated by comparing the secretion of cytokines in the MLR, and the expression of cytokine mRNA in the allografts of tolerant and nontolerant Lewis rats. Although, the 3H-thymidine incorporation and secretion of IL-2 was frequently comparable in the MLR from tolerant and nontolerant rats, the secretion of IFN-gamma was markedly reduced in the tolerant rats. This was reflected in a markedly reduced frequency of cells expressing IFN-gamma mRNA in the allografts of tolerant as compared with nontolerant hosts. The frequency of cells expressing IL-2 and IL-10 mRNA was also reduced, but no significant difference was observed for cells with IL-4 mRNA. Spleen cells from nontolerant rats rapidly rejected ACI allografts in irradiated adoptive hosts, but spleen cells from tolerant rats did not. Evaluation of the cytokine mRNA expression at early and late time points in the allografts of adoptive hosts showed a pattern similar to that of the primary hosts. Thus, the tolerant state was associated with a maintenance or elevation of IL-4 expression and a marked reduction of IFN-gamma expression. Previous reports have shown that TLI alone induced this shift in the early recovery phase after irradiation.

Upregulation of intragraft interleukin-10 by infusion of granulocyte colony-stimulating factor-mobilized donor leukocytes

Abstract.We examined the effects of granulocyte colony-stimulating factor (G-CSF)-mobilized donor leukocyte infusion (G-DLI) on facilitation of allograft survival using heart transplantation from DA to Lewis rats that were transiently treated with tacrolimus (2 mg/kg i.m. on day 0). Other DA rats were given G-CSF (250 μg/kg/day s.c. from days –5 to 0), and isolated leukocytes were infused into Lewis recipients after surgery. Cytokine mRNA levels were quantified by reverse transcription and real-time polymerase chain reaction. After G-CSF treatment, leukocytes in circulation increased by 7.6 times and secreted in-vitro 6.0-times-higher levels of IL-10 after lipopolysaccharide stimulation than did untreated leukocytes. G-DLI facilitated graft survival dose-dependently. Significant IL-10 mRNA upregulation was detected in grafts 24 h after surgery but not in the recipients heart, spleen, or liver. On day 6, IFN-γ and IL-2 mRNA levels were approximately half those of the control levels. Allograft-restricted IL-10 upregulation followed by type-1 cytokine downregulation can be achieved by the use of G-DLI.

Facilitation of tacrolimus-induced heart-allograft acceptability by pretransplant host treatment with granulocyte colony-stimulating factor: interleukin-12-restricted suppression of intragraft monokine mRNA expression.

Background. Because recombinant human granulocyte colony-stimulating factor (rhG-CSF) is known to modulate function of antigen-presenting cells, we examined effects of pretransplant host treatment with rhG-CSF on allograft survival. Methods. In DA-to-Lewis rat heart transplantation, hosts were given pretransplant injections of rhG-CSF (250 &mgr;g/kg/day subcutaneously from day −5–0) and/or posttransplant injections of tacrolimus (2 mg/kg/day intramuscularly from day 0–3). Cytokine mRNA levels in grafts were measured by real-time reverse-transcription polymerase chain reaction. Results. rhG-CSF pretreatment was effective in prolonging allograft survival only in tacrolimus-treated hosts (P <0.001). Intragraft mRNA expression of interleukin (IL)-12 subunits (p35, p40) at 24 hours after transplantation was significantly (P <0.05) down-regulated by the addition of rhG-CSF and was associated with suppression of interferon-&ggr; levels on day 6, although other proinflammatory cytokines (tumor necrosis factor -&agr;, IL-1&bgr;, IL-6, IL-18) and anti-inflammatory cytokines (IL-10, transforming growth factor-&bgr;) were not. Conclusions. rhG-CSF pretreatment down-regulates intragraft expression of the type-1 T-helper cell (Th1)-driving cytokine IL-12 and facilitates tacrolimus-induced graft acceptance.

Preventive effect of G-CSF on acute lung injury via alveolar macrophage regulation

BACKGROUND Acute lung injury and acute respiratory distress syndrome (ALI/ARDS) are devastating clinical syndromes associated with a high mortality rate. We examined the preventive effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in a mouse ALI/ARDS model induced by lipopolysaccharide (LPS). MATERIALS AND METHODS Mice were injected with LPS (10-20 mg/kg) with or without rhG-CSF pretreatment (250 mg/kg/d). Survival rate, cytokine mRNA expression, and pathologic findings were examined. RESULTS The 96-h survival rate of the control group was 20%. Survival was significantly increased to 80% in rhG-CSF-treated animals. LPS-induced destruction of the alveolar structure was not observed in the rhG-CSF group. Pretreatment with rhG-CSF led to significantly lower mRNA expression of TNF-α and IL-1β in the lung 24 h after LPS administration and significantly higher IL-10 expression 96 h after LPS administration. Immunohistochemical analysis revealed that treatment with rhG-CSF also prevented the up-regulation of TNF-α and IL-1β protein expression in alveolar macrophages. CONCLUSION Treatment with rhG-CSF prevents the development of ALI/ARDS induced by LPS by affecting the production of pro- and anti-inflammatory cytokines and may be promising in clinical applications.