RESUMO
The emergence of Omicron lineages and descendent subvariants continues to present a severe threat to the effectiveness of vaccines and therapeutic antibodies. We have previously suggested that an insufficient mucosal immunoglobulin A (IgA) response induced by the mRNA vaccines is associated with a surge in breakthrough infections. Here, we further show that the intramuscular mRNA and/or inactivated vaccines cannot sufficiently boost the mucosal secretory IgA response in uninfected individuals, particularly against the Omicron variant. We thus engineered and characterized recombinant monomeric, dimeric, and secretory IgA1 antibodies derived from four neutralizing IgG monoclonal antibodies (mAbs 01A05, rmAb23, DXP-604, and XG014) targeting the receptor-binding domain of the spike protein. Compared to their parental IgG antibodies, dimeric and secretory IgA1 antibodies showed a higher neutralizing activity against different variants of concern (VOCs), in part due to an increased avidity. Importantly, the dimeric or secretory IgA1 form of the DXP-604 antibody significantly outperformed its parental IgG antibody, and neutralized the Omicron lineages BA.1, BA.2, and BA.4/5 with a 25- to 75-fold increase in potency. In human angiotensin converting enzyme 2 (ACE2) transgenic mice, a single intranasal dose of the dimeric IgA DXP-604 conferred prophylactic and therapeutic protection against Omicron BA.5. Thus, dimeric or secretory IgA delivered by nasal administration may potentially be exploited for the treatment and prevention of Omicron infection, thereby providing an alternative tool for combating immune evasion by the current circulating subvariants and, potentially, future VOCs.
Assuntos
Anticorpos Monoclonais , Imunoglobulina A Secretora , Animais , Camundongos , Humanos , Imunoglobulina G , Imunoglobulina A , Administração Intranasal , Camundongos TransgênicosRESUMO
BACKGROUND: Costimulation blockade can prevent rejection of islet xenografts in naïve but not sensitized recipients. Donor-specific antibodies (DSA) may partly explain this observation. The effect of DSA on rat islet xenograft survival in mice receiving costimulation blockade was investigated. METHODS: Naïve C57BL/6 mice with alloxan-induced diabetes were transplanted under the left kidney capsule with 100 Lewis rat islets. Recipients were divided into three groups receiving: (i) isotype control antibodies (Abs); (ii) anti-CD154 and CTLA4Ig; or (iii) anti-CD154, CTLA4Ig, and anti-LFA-1 every second day, day 0-8. At the time of transplantation (Tx), half of the animals in each group received naïve mouse serum and half xenoimmune serum derived from mice previously transplanted with rat islets. Non-fasting blood glucose levels and body weight were followed daily. Cured mice were examined by intraperitoneal glucose tolerance (IPGT) tests at 1 and 4 months after transplantation. RESULTS: Donor-specific antibodies were detected in immune serum-injected recipients up to at least 96 h post-Tx. Short term (≤96 h), there was no significant difference with regard to graft mass, infiltrating and apoptotic cells between groups of mice receiving naïve and immune sera. A moderate infiltration of polymorphonuclear and mononuclear cells was seen 96 h post-Tx in mice given control Abs, whether or not they received immune or naïve mouse serum. Mice given costimulation blockade had well-maintained endocrine tissue and very little cell infiltration. There was no significant difference in islet xenograft function and survival long term between groups receiving naïve and immune sera in combination with costimulation blockade. About half of the mice receiving costimulation blockade lost graft function within 110 days. CONCLUSION: The presence at Tx of DSA does not appear to negatively influence early and late islet xenograft survival in mice receiving costimulation blockade.
Assuntos
Transplante das Ilhotas Pancreáticas/imunologia , Transplante Heterólogo , Animais , Anticorpos Bloqueadores/administração & dosagem , Anticorpos Bloqueadores/sangue , Anticorpos Heterófilos/administração & dosagem , Anticorpos Heterófilos/sangue , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/fisiopatologia , Diabetes Mellitus Experimental/terapia , Teste de Tolerância a Glucose , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto/imunologia , Sobrevivência de Enxerto/fisiologia , Transplante das Ilhotas Pancreáticas/efeitos adversos , Transplante das Ilhotas Pancreáticas/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Endogâmicos Lew , Fatores de Tempo , Doadores de Tecidos , Transplante Heterólogo/efeitos adversosRESUMO
Regulatory cell therapies have shown promise in tolerance-induction protocols in living donor organ transplantation. These protocols should be pursued in deceased donor transplantation. Donor peripheral mononuclear cells (PBMCs) are an optimal source of donor antigens for the induction of donor-specific regulatory cells. During the development of a regulatory cell tolerance-induction protocol with organs from deceased donors, we compared 3 methods of obtaining PBMCs from deceased donors focusing on cell yield, viability, and contamination of unwanted cell types. PBMC procurement methods: 1. During organ procurement at the time of cold perfusion, blood was collected from the vena cava and placed into a 10-liter blood collection bag, and thereafter transported to Karolinska University Hospital, where leukapheresis was performed (BCL). 2. Blood was collected via the vena cava into blood donation bags before cold perfusion. The bags underwent buffy coat separation and thereafter automated leukocyte isolation system (BCS). 3. To collect PBMCs, leukapheresis was performed via a central dialysis catheter on deceased donors in the intensive care unit (ICU) prior to the organ procurement procedure (LEU).All 3 methods to obtain PBMC from deceased donors were safe and did not affect the procurement of organs. BCL contained around 50% of NK cells in lymphocytes population. LEU had a highest yield of donor PBMC among 3 groups. LEU had the lower amount of granulocyte contamination, compared to BCS and BCL. Based on these results, we choose LEU as the preferred method to obtain donor PBMC in the development of our tolerance-induction protocol.
Assuntos
Leucaférese , Leucócitos Mononucleares , Doadores de Tecidos , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Adulto , Pessoa de Meia-Idade , Masculino , Feminino , Leucaférese/métodos , Idoso , Tolerância ImunológicaRESUMO
Growth hormone (GH) deficiency is characterized by impaired growth and development, and is currently treated by repeated administration of recombinant human GH (hGH). Encapsulated cell therapy (ECT) may offer a less demanding treatment-strategy for long-term production and release of GH into circulation. We used PiggyBac-based (PB) transposon delivery for engineering retinal pigment epithelial cells (ARPE-19), and tested a series of viral and non-viral promoters as well as codon-optimization to enhance transgene expression. Engineered cells were loaded into TheraCyte macrocapsules and secretion was followed in vitro and in vivo. The cytomegalovirus (CMV) promoter supports strong and persistent transgene expression, and we achieved clonal cell lines secreting over 6 µg hGH/106 cells/day. Codon-optimization of the hGH gene did not improve secretion. ARPE-19 cells endured encapsulation in TheraCyte devices, and resulted in steady hormone release for at least 60 days in vitro. A short-term pilot experiment in immunodeficient SCID mice demonstrated low systemic levels of hGH from a single 40 µL capsule implanted subcutaneously. No significant increase in weight increase or systemic hGH was detected after 23 days in the GH-deficient lit/SCID mouse model using 4.5 µL capsules loaded with the highest secreting clone of ARPE-19 cells. Our results demonstrate that PB-mediated engineering of ARPE-19 is an efficient way to generate hormone secreting cell lines compatible with macroencapsulation, and our CMV-driven expression cassette allows for identification of clones with high level and long-term secretory activity without addition of insulator elements. Our results pave the way for further in vivo studies of encapsulated cell therapy.
Assuntos
Infecções por Citomegalovirus , Hormônio do Crescimento Humano , Camundongos , Animais , Humanos , Hormônio do Crescimento Humano/genética , Hormônio do Crescimento Humano/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Camundongos SCID , Linhagem CelularRESUMO
The recent emergence of the Omicron variant has raised concerns on vaccine efficacy and the urgent need to study more efficient vaccination strategies. Here we observed that an mRNA vaccine booster in individuals vaccinated with two doses of inactivated vaccine significantly increased the plasma level of specific antibodies that bind to the receptor-binding domain (RBD) or the spike (S) ectodomain (S1 + S2) of both the G614 and the Omicron variants, compared to two doses of homologous inactivated vaccine. The level of RBD- and S-specific IgG antibodies and virus neutralization titers against variants of concern in the heterologous vaccination group were similar to that in individuals receiving three doses of homologous mRNA-vaccine or a boost of mRNA vaccine after infection, but markedly higher than that in individuals receiving three doses of a homologous inactivated vaccine. This heterologous vaccination regime furthermore significantly enhanced the RBD-specific memory B cell response and S1-specific T cell response, compared to two or three doses of homologous inactivated vaccine. Our study demonstrates that mRNA vaccine booster in individuals vaccinated with inactivated vaccines can be highly beneficial, as it markedly increases the humoral and cellular immune responses against the virus, including the Omicron variant.
Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos , RNA Mensageiro/genética , SARS-CoV-2/genética , Vacinação , Vacinas de Produtos Inativados , Vacinas Sintéticas , Vacinas de mRNARESUMO
During intra-portal pancreatic islet transplantation (PITx), innate immune reactions such as the instant blood mediated inflammatory reaction (IBMIR) cause an immediate loss of islets. The non-hematopoietic erythropoietin analogue cibinetide has previously shown islet-protective effects in mouse PITx. Herein, we aimed to confirm cibinetide's efficacy on human islets, and to characterize its effect on IBMIR. We cultured human islets with pro-inflammatory cytokines for 18 hours with or without cibinetide. ATP content and caspase 3/7 activity were measured. Dynamic glucose perfusion assay was used to evaluate islet function. To evaluate cibinetides effect on IBMIR, human islets were incubated in heparinized polyvinyl chloride tubing system with ABO compatible blood and rotated for 60 minutes to mimic the portal vein system. Moreover, human islets were transplanted into athymic mice livers via the portal vein with or without perioperative cibinetide treatment. The mice were sacrificed six days following transplantation and the livers were analyzed for human insulin and serum for human C-peptide levels. Histological examination of recipient livers to evaluate islet graft infiltration by CD11b+ cells was performed. Our results show that cibinetide maintained human islet ATP levels and reduced the caspase 3/7 activity during culture with pro-inflammatory cytokines and improved their insulin secreting capacity. In the PVC loop system, administration of cibinetide reduced the IBMIR-induced platelet consumption. In human islet to athymic mice PITx, cibinetide treatment showed an increased amount of human insulin in the livers and higher serum human C-peptide, while histological examination of the livers showed reduced infiltration of pro-inflammatory CD11b+ cells around islets grafts compared to the controls. In summary, Cibinetide protected isolated human islets in a pro-inflammatory milieu and reduced IBMIR related platelet consumption. It improved engraftment of human islets in athymic mice. The study confirms that cibinetide is a promising agent to be used in clinical PITx.
Assuntos
Diabetes Mellitus Experimental/terapia , Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/efeitos dos fármacos , Oligopeptídeos/uso terapêutico , Animais , Humanos , Masculino , Camundongos , Camundongos Nus , Oligopeptídeos/farmacologiaRESUMO
BACKGROUND: Monitoring the adaptive immune responses during the natural course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection provides useful information for the development of vaccination strategies against this virus and its emerging variants. We thus profiled the serum anti-SARS-CoV-2 antibody (Ab) levels and specific memory B and T cell responses in convalescent coronavirus disease 2019 (COVID-19) patients. METHODS: A total of 119 samples from 88 convalescent donors who experienced mild to critical disease were tested for the presence of elevated anti-spike and anti-receptor binding domain Ab levels over a period of 8 months. In addition, the levels of SARS-CoV-2 neutralizing Abs and specific memory B and T cell responses were tested in a subset of samples. FINDINGS: Anti-SARS-CoV-2 Abs were present in 85% of the samples collected within 4 weeks after the onset of symptoms in COVID-19 patients. Levels of specific immunoglobulin M (IgM)/IgA Abs declined after 1 month, while levels of specific IgG Abs and plasma neutralizing activities remained relatively stable up to 6 months after diagnosis. Anti-SARS-CoV-2 IgG Abs were still present, although at a significantly lower level, in 80% of the samples collected at 6-8 months after symptom onset. SARS-CoV-2-specific memory B and T cell responses developed with time and were persistent in all of the patients followed up for 6-8 months. CONCLUSIONS: Our data suggest that protective adaptive immunity following natural infection of SARS-CoV-2 may persist for at least 6-8 months, regardless of disease severity. Development of medium- or long-term protective immunity through vaccination may thus be possible. FUNDING: This project was supported by the European Union's Horizon 2020 research and innovation programme (ATAC, no. 101003650), the Italian Ministry of Health (Ricerca Finalizzata grant no. GR-2013-02358399), the Center for Innovative Medicine, and the Swedish Research Council. J.A. was supported by the SciLifeLab/KAW national COVID-19 research program project grant 2020.
Assuntos
COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Humanos , Imunoglobulina A , Imunoglobulina G , Linfócitos TRESUMO
BACKGROUND: ABO blood group antigens in the liver are expressed mainly on endothelial cells or biliary epithelial cells but not on hepatocytes. This suggests that ABO-incompatible hepatocyte transplantation (ABOi-HTx) is theoretically feasible. However, the effects of stress on ABO blood group antigen expression caused by isolation and intraportal infusion require thorough investigation before ABOi-HTx can be implemented in clinical settings. METHODS: Human hepatocytes were isolated from liver tissue obtained from liver resection or deceased donor livers. The expression of blood group antigens on cryopreserved human liver tissues and isolated hepatocyte smear specimens were examined by immunofluorescent staining. The effect of proinflammatory cytokines on blood group antigen expression of hepatocytes was evaluated by flow cytometry. Instant blood-mediated inflammatory reaction after hepatocyte incubation with ABO-incompatible whole blood was examined using the tubing loop model. RESULTS: Blood group antigens were mainly expressed on vessels in the portal area. In hepatocyte smear specimens, isolated hepatocytes did not express blood group antigens. In contrast, a subset of cells in the smear specimens of nonparenchymal liver cells stained positive. In the flow cytometry analysis, isolated hepatocytes were negative for blood group antigens, even after 4-h incubation with cytokines. Platelet counts and complement activation were not significantly different in ABO-identical versus ABO-incompatible settings in the tubing loop model. CONCLUSION: Our study showed that blood group antigens were not expressed on hepatocytes, even after isolation procedures or subsequent incubation with cytokines. This finding is an important step toward removing the restriction of ABO matching in hepatocyte transplantation. Our results suggest that ABOi-HTx is a feasible therapeutic option, especially in patients who require urgent treatment with freshly isolated hepatocytes, such as those with acute liver failure.
RESUMO
BACKGROUND: During intraportal pancreatic islet transplantation (PITx), early inflammatory reactions cause an immediate loss of more than half of the transplanted graft and potentiate subsequent allograft rejection. Previous findings suggest that cibinetide, a selective innate repair receptor agonist, exerts islet protective and antiinflammatory properties and improved transplant efficacy in syngeneic mouse PITx model. In a stepwise approach toward a clinical application, we have here investigated the short- and long-term effects of cibinetide in an allogeneic mouse PITx model. METHODS: Streptozotocin-induced diabetic C57BL/6N (H-2) mice were transplanted with 320 (marginal) or 450 (standard) islets from BALB/c (H-2) mice via the portal vein. Recipients were treated perioperative and thereafter daily during 14 d with cibinetide (120 µg/kg), with or without tacrolimus injection (0.4 mg/kg/d) during days 4-14 after transplantation. Graft function was assessed using nonfasting glucose measurements. Relative gene expressions of proinflammatory cytokines and proinsulin of the graft-bearing liver were assessed by quantitative polymerase chain reaction. Cibinetide's effects on dendritic cell maturation were investigated in vitro. RESULTS: Cibinetide ameliorated the local inflammatory responses in the liver and improved glycemic control immediately after allogeneic PITx and significantly delayed the onset of allograft loss. Combination treatment with cibinetide and low-dose tacrolimus significantly improved long-term graft survival following allogeneic PITx. In vitro experiments indicated that cibinetide lowered bone-marrow-derived-immature-dendritic cell maturation and subsequently reduced allogeneic T-cell response. CONCLUSIONS: Cibinetide reduced the initial transplantation-related severe inflammation and delayed the subsequent alloreactivity. Cibinetide, in combination with low-dose tacrolimus, could significantly improve long-term graft survival in allogeneic PITx.
Assuntos
Anti-Inflamatórios/farmacologia , Glicemia/efeitos dos fármacos , Diabetes Mellitus Experimental/terapia , Sobrevivência de Enxerto/efeitos dos fármacos , Imunossupressores/farmacologia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/cirurgia , Oligopeptídeos/farmacologia , Animais , Glicemia/metabolismo , Células Cultivadas , Citocinas/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/imunologia , Quimioterapia Combinada , Mediadores da Inflamação/metabolismo , Ilhotas Pancreáticas/imunologia , Ilhotas Pancreáticas/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Tacrolimo/farmacologia , Fatores de TempoRESUMO
In order to study the ability of costimulation blockade to induce tolerance to human embryonic stem cells (HESC), severe combined immunodeficient (SCID), and immunocompetent C57BL/6 mice treated with costimulation blockade received intratesticular and intramyocardial HESC transplants. All SCID mice with intratesticular HESC transplants developed teratoma. When SCID mice were transplanted intramyocardially, only two of five mice developed teratoma-like tumors. C57BL/6 mice transplanted intratesticularly and treated with costimulation blockade all developed teratoma and were surrounded by CD4(+)CD25(+)Foxp3(+) T-cells, while isotype control treated recipients rejected their grafts. Most C57BL/6 mice transplanted intramyocardially and treated with costimulation blockade demonstrated lymphocytic infiltrates 1 month after transplantation, whereas one maintained its graft. Isolation of regulatory T-cells from intramyocardial transplanted recipients treated with costimulation blockade demonstrated specificity toward undifferentiated HESC and down-regulated naive T-cell activation toward HESC. These results demonstrate that costimulation blockade is sufficiently robust to induce tolerance to HESC in the immune-privileged environment of the testis. HESC specific regulatory T-cells developed to HESC transplanted to the heart and the success of transplantation was similar to that seen in SCID mice.
Assuntos
Transplante de Células/métodos , Células-Tronco Embrionárias/citologia , Miocárdio/metabolismo , Linfócitos T Reguladores/citologia , Testículo/metabolismo , Animais , Linfócitos T CD4-Positivos/metabolismo , Ligante de CD40/biossíntese , Células-Tronco Embrionárias/metabolismo , Humanos , Tolerância Imunológica/imunologia , Subunidade alfa de Receptor de Interleucina-2/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCIDRESUMO
Islet graft survival inside macroencapsulation devices is suboptimal. We hypothesized that induction of neovascularization by preimplantation of devices would improve the physiological conditions, thereby lowering the number of islets required for cure. Several rat islets were transplanted to TheraCyte immunoprotective devices implanted subcutaneously in diabetic athymic mice. Cure rates in the groups with preimplanted devices were significantly better than in those with freshly implanted devices (375 islets: 8/8 vs. 1/6, P=0.003; 125 islets: 6/6 vs. 0/7, P=0.001). Morphometric evaluations of the 125 islet groups showed higher fractional and absolute volumes of endocrine tissue in the group with preimplanted devices (P<0.001 and P=0.035, respectively). In the following dose titration study, using preimplanted devices, as low as 50 islets cured diabetic mice (100% cure, n=6). We conclude that preimplantation significantly lowers the curative dose of macroencapsulated islets to levels resembling those of free islets transplanted under the renal capsule.
Assuntos
Transplante das Ilhotas Pancreáticas/métodos , Ilhotas Pancreáticas/citologia , Animais , Diabetes Mellitus Experimental/terapia , Sistema Endócrino , Desenho de Equipamento , Feminino , Glucose/metabolismo , Teste de Tolerância a Glucose , Sobrevivência de Enxerto , Camundongos , Camundongos Nus , Implantação de Prótese , Fatores de Tempo , Resultado do TratamentoRESUMO
Adoptive transfer of alloantigen-specific immunomodulatory cells generated ex vivo with anti-CD80/CD86 mAbs (2D10.4/IT2.2) holds promise for operational tolerance after transplantation. However, good manufacturing practice is required to allow widespread clinical application. Belatacept, a clinically approved cytotoxic T-lymphocyte antigen 4-immunoglobulin that also binds CD80/CD86, could be an alternative agent for 2D10.4/IT2.2. With the goal of generating an optimal cell treatment with clinically approved reagents, we evaluated the donor-specific immunomodulatory effects of belatacept- and 2D10.4/IT2.2-generated immunomodulatory cells. Immunomodulatory cells were generated by coculturing responder human peripheral blood mononuclear cells (PBMCs) (50 × 106 cells) with irradiated donor PBMCs (20 × 106 cells) from eight human leukocyte antigen-mismatched responder-donor pairs in the presence of either 2D10.4/IT2.2 (3 µg/106 cells) or belatacept (40 µg/106 cells). After 14 days of coculture, the frequencies of CD4+ T cells, CD8+ T cells, and natural killer cells as well as interferon gamma (IFN-γ) production in the 2D10.4/IT2.2- and belatacept-treated groups were lower than those in the control group. The percentage of CD19+ B cells was higher in the 2D10.4/IT2.2- and belatacept-treated groups than in the control group. The frequency of CD4+CD25+CD127lowFOXP3+ T cells increased from 4.1±1.0% (preculture) to 7.1±2.6% and 7.3±2.6% (day 14) in the 2D10.4/IT2.2- and belatacept-treated groups, respectively (p<0.05). Concurrently, delta-2 FOXP3 mRNA expression increased significantly. Compared with cells derived from the no-antibody treated control group, cells generated from both the 2D10.4/IT2.2- and belatacept-treated groups produced lower IFN-γ and higher interleukin-10 levels in response to donor-antigens, as detected by enzyme-linked immunospot. Most importantly, 2D10.4/IT2.2- and belatacept-generated cells effectively impeded the proliferative responses of freshly isolated responder PBMCs against donor-antigens. Our results indicate that belatacept-generated donor-specific immunomodulatory cells possess comparable phenotypes and immunomodulatory efficacies to those generated with 2D10.4/IT2.2. We suggest that belatacept could be used for ex vivo generation of clinical grade alloantigen-specific immunomodulatory cells for tolerance induction after transplantation.
RESUMO
BACKGROUND: It has been previously demonstrated that addition of anti-LFA-1 to a combination of CTLA4Ig and anti-CD40L induces the permanent acceptance of dopaminergic fetal pig xenografts when transplanted into the brain of wild-type mice. The purpose of this study was to test whether this costimulation blockade also can induce acceptance of adult pig islets transplanted to C57BL/6 mice with streptozotocin-induced diabetes. METHODS: Recipients were treated with CTLA4Ig/anti-CD40L+/-anti-LFA-1 or isotype control antibodies during the first week after transplantation. Half of the costimulation blockade-treated recipients had their grafts removed after 8 weeks. The other half was observed up to 5 months. RESULTS: Recipients treated with CTLA4Ig/anti-CD40L/anti-LFA-1 had significantly lower blood glucose and gained more weight than CTLA4Ig/anti-CD40L-treated recipients. CTLA4Ig/anti-CD40L-treated recipients exhibited unstable blood glucose. IPGTT of these recipients revealed a slow recovery to normal blood glucose levels at week 4. In comparison, CTLA4Ig/anti-CD40L/anti-LFA-1 treated recipients exhibited a significantly superior glucose clearance. CTLA4Ig/anti-CD40L+/-anti-LFA-1 treated recipients did not produce anti-pig IgG, whereas control antibody-treated mice did. CD4+ T cells from costimulation blockade-treated recipients proliferated less than CD4+ T cells from control antibody-treated mice when co-cultured with syngeneic antigen presenting cells loaded with pig islet antigens. CONCLUSIONS: CTLA4Ig/anti-CD40L/anti-LFA-1-treated recipients had superior islet function compared with CTLA4Ig/anti-CD40L-treated recipients. However, both costimulation blockade regimens led to islet graft acceptance up to 5 months after a 1-week treatment.
Assuntos
Anticorpos/farmacologia , Ligante de CD40/imunologia , Diabetes Mellitus Experimental/cirurgia , Imunoconjugados/farmacologia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/fisiopatologia , Antígeno-1 Associado à Função Linfocitária/imunologia , Transplante Heterólogo , Abatacepte , Animais , Glicemia/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Proliferação de Células , Diabetes Mellitus Experimental/sangue , Epitopos , Feminino , Glucose/farmacologia , Imunoglobulina G/biossíntese , Imunoglobulina G/imunologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/patologia , Leucócitos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Suínos , Fatores de TempoRESUMO
BACKGROUND: Erythropoietin exerts anti-inflammatory, antiapoptotic, and cytoprotective effects in addition to its hematopoietic action. A nonhematopoietic erythropoietin analogue, ARA 290, has similar properties. The efficacy of pancreatic islet transplantation (PITx) is reduced due to islet damage that occurs during isolation and from the severe inflammatory reactions caused by the transplantation procedure. We investigated whether ARA 290 protects islets and ameliorates inflammatory responses following PITx thus improving engraftment. METHODS: The effects of ARA 290 on pancreatic islets of C57BL/6J (H-2) mice and on murine macrophages were investigated using an in vitro culture model. As a marginal PITx, 185 islets were transplanted into the liver of streptozotocin-induced diabetic mice (H-2) via the portal vein. Recipients were given ARA 290 (120 µg/kg) intraperitoneally just before and at 0, 6, and 24 hours after PITx. Liver samples were obtained at 12 hours after PITx, and expression levels of proinflammatory cytokines were assessed. RESULTS: ARA 290 protected islets from cytokine-induced damage and apoptosis. Secretion of pro-inflammatory cytokines (IL-6, IL-12, and TNF-α) from macrophages was significantly inhibited by ARA 290. After the marginal PITx, ARA 290 treatment significantly improved the blood glucose levels when compared to those of control animals (P < 0.001). Upregulation of monocyte chemoattractant protein-1, macrophage inflammatory protein-1ß, IL-1ß, and IL-6 messenger RNA expression within the liver was suppressed by ARA 290 treatment. CONCLUSIONS: ARA 290 protected pancreatic islets from cytokine-induced damage and apoptosis and ameliorated the inflammatory response after PITx. ARA 290 appears to be a promising candidate for improvement of PITx.
Assuntos
Apoptose/efeitos dos fármacos , Diabetes Mellitus Experimental/cirurgia , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/cirurgia , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Oligopeptídeos/farmacologia , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Células Cultivadas , Citocinas/metabolismo , Citoproteção , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Relação Dose-Resposta a Droga , Esquema de Medicação , Hepatite/imunologia , Hepatite/metabolismo , Hepatite/prevenção & controle , Mediadores da Inflamação/metabolismo , Injeções Intraperitoneais , Ilhotas Pancreáticas/imunologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Oligopeptídeos/administração & dosagem , Fatores de TempoRESUMO
Streptozotocin (STZ) and alloxan (ALX), widely used to induce diabetes in experimental animals, have different structures and mechanisms of action. We investigated those effects of these drugs on the immune system that might influence engraftment efficiency and graft survival in transplantation models, and their cytotoxicity on hematopoietic cell lines. We used the minimum dose to induce diabetes in a mouse, i.e. 180 mg/kg i.v. STZ and 75 mg/kg i.v. ALX. Both groups exhibited significant decrease in body weight during 4 days post-treatment as compared to controls. We found that blood glucose in ALX-injected mice increased faster than in STZ-injected mice. The total number of recovered splenocytes was lower in STZ-injected animals than in ALX-injected animals. The survival periods of rat islet grafts in recipient mice were longer and more diverse in STZ-injected recipients (7-24 days) compared to ALX-injected recipients (6-7 days). The in vitro study showed that ALX was less cytotoxic in cell lines with IC50 values of 2809, 3679 and >4000 µg/ml for HL60, K562 and C1498 cells respectively. STZ was more toxic, especially in HL60 cells, with IC50 values of 11.7, 904 and 1024 µg/ml for HL60, K562 and C1498 cells respectively. Furthermore, in response to concanavalin A (Con-A), splenocytes from STZ-injected mice produced higher amounts of interferon-gamma (IFN-γ) than those from ALX-injected mice. In conclusion, STZ was more cytotoxic than ALX in vitro and in vivo. STZ caused lymphocytopenia, which may result in longer graft survival in STZ-treated animals than in ALX-treated animals.
Assuntos
Aloxano/toxicidade , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Experimental/fisiopatologia , Estreptozocina/toxicidade , Aloxano/imunologia , Animais , Glicemia/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/imunologia , Células HL-60 , Humanos , Concentração Inibidora 50 , Transplante das Ilhotas Pancreáticas/imunologia , Transplante das Ilhotas Pancreáticas/métodos , Transplante das Ilhotas Pancreáticas/mortalidade , Células K562 , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Ratos Endogâmicos Lew , Baço/efeitos dos fármacos , Baço/metabolismo , Baço/patologia , Estreptozocina/imunologia , Taxa de Sobrevida , Fatores de Tempo , Transplante HeterólogoRESUMO
Apolipoprotein (Apo) D is an important protein produced in many parts of the body. It is necessary for the development and repair of the brain and protection from oxidative stress. The purpose of this study was to investigate the extent to which apoD interacts with lipoproteins in human plasma. By using detergent-free ELISA, we show that immobilized monoclonal antibodies against apoD very efficiently bind to low density lipoprotein (LDL) from plasma; this binding is as equally efficient as binding to an anti-apoB monoclonal antibody. Adding detergent to the plasma inhibited the binding, suggesting that the binding is dependent on the presence of intact lipoprotein particles. Reversing the system by using immobilized anti-apoB revealed that the affinity of apoD for LDL is rather low, suggesting that multiple bindings are needed for a durable connection. Biosensor experiments using purified lipoproteins also showed that purified apoD and high density lipoprotein 3 (HDL3), a lipoprotein fraction rich in apoD, were both able to bind LDL very efficiently, indicating that the HDL3-LDL interaction may be a physiological consequence of the affinity of apoD for LDL. Furthermore, we found that apoD increases the binding of HDL to actively growing T24 bladder carcinoma cells but not to quiescent, contact-inhibited, confluent T24 cells. This result is especially intriguing given that the T24 supernatant only contained detectable levels of apoD after growth inhibition, raising the possibility that alternating the expression of apoD and a putative apoD-receptor could give direction to the flow of lipids. In the current paper, we conclude that apoD mediates binding of HDL to LDL and to growing T24 carcinomas, thereby highlighting the importance of apoD in lipid metabolism.
Assuntos
Apolipoproteínas D/metabolismo , Carcinoma/metabolismo , Lipoproteínas HDL/metabolismo , Lipoproteínas LDL/metabolismo , Neoplasias da Bexiga Urinária/metabolismo , Anticorpos Monoclonais/imunologia , Apolipoproteínas D/sangue , Apolipoproteínas D/imunologia , Linhagem Celular Tumoral , Ensaio de Imunoadsorção Enzimática , Humanos , Lipoproteínas HDL/sangue , Lipoproteínas LDL/sangue , Ligação ProteicaRESUMO
Multipotent mesenchymal stromal cell (MSC) therapy and costimulation blockade are two immunomodulatory strategies being developed concomitantly for the treatment of immunological diseases. Both of these strategies have the capacity to inhibit immune responses and induce regulatory T cells; however, their ability to synergize remains largely unexplored. In order to study this, MSCs from C57BL/6 (H2b) mice were infused together with fully major histocompatibility complex-mismatched Balb/c (H2d) allogeneic islets into the portal vein of diabetic C57BL/6 (H2b) mice, which were subsequently treated with costimulation blockade for the first 10 days after transplantation. Mice receiving both recipient-type MSCs, CTLA4Ig, and anti-CD40L demonstrated indefinite graft acceptance, just as did most of the recipients receiving MSCs and CTLA4Ig. Recipients of MSCs only rejected their grafts, and fewer than one half of the recipients treated with costimulation blockade alone achieved permanent engraftment. The livers of the recipients treated with MSCs plus costimulation blockade contained large numbers of islets surrounded by Foxp3+ regulatory T cells. These recipients showed reduced antidonor IgG levels and a glucose tolerance similar to that of naïve nondiabetic mice. Intrahepatic lymphocytes and splenocytes from these recipients displayed reduced proliferation and interferon-γ production when re-exposed to donor antigen. MSCs in the presence of costimulation blockade prevented dendritic cell maturation, inhibited T cell proliferation, increased Foxp3+ regulatory T cell numbers, and increased indoleamine 2,3-dioxygenase activity. These results indicate that MSC infusion and costimulation blockade have complementary immune-modulating effects that can be used for a broad number of applications in transplantation, autoimmunity, and regenerative medicine.
Assuntos
Diabetes Mellitus Experimental , Células Secretoras de Insulina , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/imunologia , Células-Tronco Multipotentes/imunologia , Linfócitos T Reguladores/imunologia , Aloenxertos , Animais , Proliferação de Células , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Experimental/terapia , Fatores de Transcrição Forkhead/imunologia , Imunoglobulina G/imunologia , Indolamina-Pirrol 2,3,-Dioxigenase/imunologia , Células Secretoras de Insulina/imunologia , Células Secretoras de Insulina/transplante , Interferon gama/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Linfócitos T Reguladores/patologiaRESUMO
The apoE production by tissue macrophages is crucial for the prevention of atherosclerosis and the aim of this study was to further elucidate how this apolipoprotein is regulated by cytokines present during inflammation. Here we studied apoE production in peripheral blood mononuclear cells (PBMC) and analysis was made with a newly developed apoE ELISpot assay. In PBMC, apoE secretion was restricted to monocytes with classical (CD14(++)CD16(-)) and intermediate (CD14(+)CD16(+)) monocytes being the main producers. As earlier described for macrophages, production was strongly upregulated by TGF-ß and downregulated by bacterial lipopolysaccharide (LPS) and the inflammatory cytokines IFN-γ, TNF-α and IL-1ß. We could here show that a similar down-regulatory effect was also observed with the type I interferon, IFN-α, while IL-6, often regarded as one of the more prominent inflammatory cytokines, did not affect TGF-ß-induced apoE production. The TNF-α inhibitor Enbrel could partly block the down-regulatory effect of IFN-γ, IFN-α and IL-1ß, indicating that inhibition of apoE by these cytokines may be dependent on or synergize with TNF-α. Other cytokines tested, IL-2, IL-4, IL-12, IL-13, IL-17A and IL-23, had no inhibitory effect on apoE production. In contrast to the effect on monocytes, apoE production by primary hepatocytes and the hepatoma cell line HepG2 was more or less unaffected by treatment with cytokines or LPS.
Assuntos
Apolipoproteínas E/biossíntese , Interferon gama/farmacologia , Interleucina-1beta/farmacologia , Monócitos/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Apolipoproteínas E/imunologia , Biomarcadores/metabolismo , Etanercepte , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/imunologia , Expressão Gênica , Células Hep G2 , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/imunologia , Humanos , Imunoglobulina G/farmacologia , Fatores Imunológicos/farmacologia , Interleucina-6/farmacologia , Receptores de Lipopolissacarídeos/genética , Receptores de Lipopolissacarídeos/imunologia , Lipopolissacarídeos/farmacologia , Monócitos/citologia , Monócitos/imunologia , Cultura Primária de Células , Receptores de IgG/genética , Receptores de IgG/imunologia , Receptores do Fator de Necrose Tumoral , Fator de Crescimento Transformador beta/farmacologia , Fator de Necrose Tumoral alfa/antagonistas & inibidoresRESUMO
Clinically, many candidates for islet transplantation are already immunized, which increases their risk of graft rejection. Encapsulation of pancreatic islets using the TheraCyte™ device has been shown to protect against allograft rejection in nonimmunized recipients. However, the capacity of the TheraCyte™ device to prevent rejection in immunized recipients has not yet been studied. In this study, the protective capacity of the TheraCyte™ device was evaluated in an allogeneic rat model. Lewis rats were used as islet donors, and nonimmunized (control) and alloimmunized, diabetic Wistar-Furth (WF) rats were used as recipients. Graft survival was shorter in immunized recipients than in nonimmunized recipients (mean survival, 5.3 ± 2.7 and 9.3 ± 1.6 days, respectively, p < 0.01) when nonencapsulated islets were transplanted under the kidney capsule. When islets were transplanted into the TheraCyte™ device, graft function was maintained during the 6-month study period in both immunized and nonimmunized rats. In oral glucose tolerance tests performed at 1 month after transplantation, both groups had similar insulin and blood glucose levels indicating similar metabolic functions. Volume densities and absolute volumes of tissue inside the devices 6 months after transplantation were also comparable between the two groups, indicating that both groups maintained similar amounts of endocrine tissue. A higher number of IFN-γ-producing CD8+ T-cells were detected in immunized WF rats compared to control WF rats transplanted with encapsulated islets. This suggests that donor-specific alloreactivity in recipient rats was sustained throughout the study period. This study suggests that the TheraCyte™ device protects islet allografts also in immunized recipients. Our results further highlight the potential for using macroencapsulation to avoid immunosuppressive therapy in clinical islet transplantation.