RESUMO
At the heart of lineage commitment within the adaptive immune response is the intrinsic genetic plasticity of the naive peripheral T lymphocyte (T cell). Primary activation by presentation of cognate antigen is coupled to rapid T-cell cycling and progressive epigenetic changes that guide the cell down distinct T-cell lineages, either effector (Th1, Th2, Th17) or tolerogenic (Treg). Fate choice is influenced both by strength of the priming activation signal and by cues from the micro-environment that are integrated with lineage-specific gene expression profiles, eventually becoming hard-wired in the fully differentiated cell. The micro-environmental cues include cytokines, and the discovery that leukaemia inhibitory factor (LIF) and interleukin (IL)-6 counter-regulate development of the Treg and Th17 lineages places LIF within the core regulatory circuitry of T cells. I first summarise current understanding of LIF and the LIF receptor in the context of T cells. Next, the central relevance of the LIF/IL-6 axis in immune-mediated disease is set in the context of (i) a new nano-therapeutic approach for targeted delivery of LIF and (ii) MARCH-7, a novel E3-ligase discovered to have a central mechanistic role in LIF-mediated T-cell biology, functioning as a rheostat-type regulator of endogenous LIF-signalling.
Assuntos
Fator Inibidor de Leucemia/metabolismo , Linfócitos T/metabolismo , Animais , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/genética , Humanos , Tolerância Imunológica/genética , Interleucina-6/metabolismo , Fator Inibidor de Leucemia/farmacologia , Fator Inibidor de Leucemia/uso terapêutico , Esclerose Múltipla/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Células Th17/imunologiaRESUMO
BACKGROUND: Donor-specific tolerance can be induced in mice by transient antibody blockade of the CD4 and CD8 co-receptors of T cells. To evaluate the potential application of CD4/CD8 blockade in the clinic, we have asked if either tacrolimus or cyclosporine counteract the tolerogenic process. METHODS: Using the fully mismatched mouse cervical heart transplant model, BALB/c (H2d) to CBA (H2k), the experimental groups were (i) no therapy, (ii) tacrolimus (1 mg/kg, i.p., daily, days 0-14); (iii) cyclosporine (25 mg/kg, i.p., daily, days 0-14), (iv) blocking monoclonal antibodies (mAbs) to CD4 and CD8 (2 mg, i.p., starting day 0 and on alternating days thereafter for a total of six doses), (v) tacrolimus plus mAbs, and (vi) cyclosporine plus mAbs. RESULTS: Allograft survival was prolonged in both the tacrolimus and cyclosporine groups. mAbs alone induced tolerance, and mAbs combined with tacrolimus also induced tolerance. In contrast, the combination of mAbs and cyclosporine was toxic. CONCLUSIONS: The induction of tolerance by blocking CD4 and CD8 was not prevented by tacrolimus. However, combination of cyclosporine with the same tolerogenic protocol was toxic to mice.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Ciclosporina/uso terapêutico , Tolerância Imunológica , Imunossupressores/uso terapêutico , Tacrolimo/uso terapêutico , Animais , Anticorpos Monoclonais/efeitos adversos , Ciclosporina/efeitos adversos , Combinação de Medicamentos , Quimioterapia Combinada , Sobrevivência de Enxerto/efeitos dos fármacos , Transplante de Coração/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Transplante de Pele/imunologia , Tacrolimo/efeitos adversos , Fatores de Tempo , Doadores de TecidosRESUMO
BACKGROUND: FK506 perturbs normal phosphorylation by inhibition of the PP2B protein phosphatase, calcineurin. Calcineurin activity is required for intracellular signal transduction via the T cell receptor that in turn leads to either TH1, or TH2, -type responses to antigen. This choice of response involves differential phosphorylation of STATS (Signal Transducers and Activators of Transcription) for induction of STAT activity. Interferon-gamma activates STAT1, a TH1-type mediator, and interleukin-4 activates STAT6, a TH2-type mediator. We ask if FK506 biases STAT activation toward a TH2-type response. METHODS: Cells of the RAW 264.7 mouse macrophage line were treated with interleukin-4, or interferon-gamma, plus or minus FK506, and any effect on STAT6 and STAT1 was compared. RESULTS: Interleukin-4 specifically induced activation of STAT6, and pretreatment with FK506 enhanced this activity. Interferon-y induced STAT1 activity but this was not influenced by FK506 pretreatment. CONCLUSION: FK506 protects against allograft rejection by inhibiting interleukin-2 production. Such protection may be enhanced by FK506-mediated up-regulation of STAT6 activity.
Assuntos
Imunossupressores/farmacologia , Interleucina-4/farmacologia , Tacrolimo/farmacologia , Transativadores/metabolismo , Animais , Linhagem Celular , Sinergismo Farmacológico , Interferon gama/farmacologia , Macrófagos/metabolismo , Camundongos , Fator de Transcrição STAT6 , Regulação para CimaAssuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Ciclosporina/uso terapêutico , Sobrevivência de Enxerto/imunologia , Transplante de Coração/imunologia , Tacrolimo/uso terapêutico , Animais , Ciclosporina/sangue , Quimioterapia Combinada , Sobrevivência de Enxerto/efeitos dos fármacos , Terapia de Imunossupressão/métodos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Tacrolimo/sangue , Transplante HomólogoAssuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Sobrevivência de Enxerto/imunologia , Transplante de Coração/imunologia , Tacrolimo/uso terapêutico , Animais , Portadores de Fármacos , Quimioterapia Combinada , Teste de Histocompatibilidade , Lipossomos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Tacrolimo/administração & dosagem , Tacrolimo/farmacocinéticaRESUMO
BACKGROUND: Transforming growth factor beta-1 (TGFbeta1) is pro-fibrotic in addition to being a potent immunosuppressive cytokine. Cyclosporine (cyclosporin A[CsA]) has been found to increase circulating TGFbeta1 levels in patients (1, 2). To determine whether tacrolimus (FK506) similarly increases TGFbeta1 we have measured TGFbeta levels in blood samples from liver graft recipients who were of known TGFbeta1-responder status. METHODS: Sequential serum and plasma samples were obtained from liver transplant recipients in the UK trial of tacrolimus versus microemulsified CsA, with a follow up period of between 50 and 265 days. Twelve patients received CsA and 13 received tacrolimus. Active and total TGFbeta1 protein were measured and plasma beta thromboglobulin (betaTG) levels were used as an indirect indication of platelet-derived TGFbeta contamination of samples. RESULTS: We found no correlation between trough drug levels and active TGFbeta1 levels in serum of either set of patients. Plasma beta thromboglobulin was detected in platelet-depleted plasma samples, indicative of platelet damage before plasma separation. CONCLUSION: Neither CsA nor tacrolimus induced active TGFbeta1 blood levels in liver transplant recipients during a follow up period of < or = 265 days.
Assuntos
Ciclosporina/farmacologia , Imunossupressores/farmacologia , Transplante de Fígado/imunologia , Tacrolimo/farmacologia , Fator de Crescimento Transformador beta/sangue , Estudos de Coortes , Ciclosporina/sangue , Humanos , Imunossupressores/sangue , Tacrolimo/sangue , Fatores de TempoRESUMO
BACKGROUND: FK506 is a potent immunosuppressant that has improved clinical outcomes in kidney and liver transplantation both as a primary and as a rescue immunosuppressive agent. Despite these benefits, the potential value of FK506 is limited by toxic side effects that result in a narrow therapeutic index. By encapsulating the active drug within liposomes (LipoFK506), a new formulation has been developed that might improve this therapeutic index. METHODS: The biodistribution of tritiated-FK506 administered i.v. showed that the drug remained associated with the liposomal carrier in vivo, and that its tissue distribution was increased in heart and spleen compared to nonliposomal FK506. The immunosuppressive efficacy of lipoFK506 compared with conventional FK506 formulation was tested in vivo. CBA (H2k) mice were engrafted with BALB/c (H2d) mouse hearts with daily immunosuppression using either 1 mg/kg FK506, or 1 mg/kg LipoFK506, from day 0 to 14. RESULTS: At day 7 the blood trough level of FK506 in the FK506 group was 10-fold higher (25 microg/L) than that in the LipoFK506 group. In both groups the median heart allograft survival was similar at around 26 days. The possibility that FK506, or LipoFK506, might influence antibody-mediated tolerogenesis was addressed in the same model: neither formulation prevented tolerance induction by CD4 and CD8 blockade. CONCLUSION: LipoFK506 is a novel formulation of FK506 that is efficacious at low blood trough FK506 levels. This property has a direct potential benefit for clinical organ transplantation.
Assuntos
Transplante de Coração/imunologia , Tacrolimo/administração & dosagem , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Interações Medicamentosas , Sobrevivência de Enxerto/efeitos dos fármacos , Sobrevivência de Enxerto/imunologia , Lipossomos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Sistema Fagocitário Mononuclear/metabolismo , Tacrolimo/sangue , Tacrolimo/farmacocinética , Tacrolimo/farmacologia , Distribuição Tecidual , Transplante HomólogoAssuntos
Transplante de Coração/imunologia , Terapia de Imunossupressão/métodos , Timo/imunologia , Transferência Adotiva , Animais , Anticorpos Monoclonais/farmacologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Depleção Linfocítica , Transfusão de Linfócitos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Timectomia , Transplante HomólogoAssuntos
Genes p53 , Imunossupressores/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , Sirolimo/farmacologia , Tacrolimo/farmacologia , Transcrição Gênica/efeitos dos fármacos , Proteína Supressora de Tumor p53/genética , Animais , Sistema Livre de Células , Camundongos , RNA Mensageiro/metabolismo , Coelhos , Reticulócitos/metabolismo , Proteína Supressora de Tumor p53/biossínteseRESUMO
BACKGROUND: Antibodies targeting recipient major histocompatibility complex (MHC) class II molecules have been demonstrated to be effective at prolonging allograft survival. However, antigen-presenting cell depletion would explain this effect and has not been definitively excluded as the mechanism of action of such antibodies. We have studied an anti-MHC class II antibody (OX6) proven to be noncytotoxic in the recipient strain used. METHODS: Antibody was administered the day before, 2 hr before, and the day after grafting. RESULTS: Antibody administration on the day before, 2 hr before, and the day after grafting significantly prolonged vascularized cardiac allograft survival. Importantly, treatment recognizing recipient MHC was effective, whereas a similar regimen recognizing donor MHC was not. CONCLUSIONS: Noncytotoxic recipient MHC class II-specific antibodies modify allograft rejection. Possible mechanisms for this therapeutic effect are discussed.
Assuntos
Anticorpos/farmacologia , Transplante de Coração/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Vasos Coronários/transplante , Citotoxicidade Imunológica , Sobrevivência de Enxerto/imunologia , Sobrevivência de Enxerto/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Condicionamento Pré-Transplante , Transplante Homólogo/imunologiaRESUMO
Certain growth regulatory kinases contain a common domain related to the phospho-inositol 3 (PI-3) kinase catalytic site. These include the ATM gene product, DNA-PKcs, and the target of rapamycin (TOR in yeast; and FRAP in mammalian cells). Rapamycin inhibits growth factor signalling and induces G1 arrest in many cell types. Some growth regulatory PI-3 kinases appear functionally linked to p53 and we have explored potential links between cellular effects induced by rapamycin and p53. In p53 null cells rapamycin inhibited cell cycling but did not induce G1 arrest. In cells which showed selective G1 arrest in response to rapamycin, rapamycin had no effect on basal levels of p53 protein. Similarly p21(WAF1) protein was not induced by rapamycin. The kinetics of the cellular p53/p21(WAF1) response to ionising radiation was unaffected by rapamycin; and the ability of growth factor to protect against p53-mediated apoptosis in response to DNA damage was also unaffected by rapamycin. The ATM gene is mutated in the cancer susceptibility syndrome ataxia telangiectasia (AT) but such mutant cells showed a similar sensitivity to rapamycin compared to their normal counterparts. RKO cell lines of common genetic background, but with different levels of functional p53 protein, also responded similarly to rapamycin. Thus, although rapamycin and p53 are each able to induce G1 arrest, they appear to act through independent growth regulatory pathways.
Assuntos
Ciclo Celular , Fase G1 , Inibidores do Crescimento/farmacologia , Imunofilinas , Fosfotransferases (Aceptor do Grupo Álcool) , Polienos/farmacologia , Proteínas Serina-Treonina Quinases , Proteína Supressora de Tumor p53/fisiologia , Animais , Proteínas Mutadas de Ataxia Telangiectasia , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular , Linhagem Celular , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/metabolismo , Proteínas de Ligação a DNA , Humanos , Interleucina-3/farmacologia , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Proteínas Proto-Oncogênicas c-akt , Sirolimo , Serina-Treonina Quinases TOR , Células Tumorais Cultivadas , Proteínas Supressoras de TumorAssuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Sobrevivência de Enxerto/imunologia , Terapia de Imunossupressão/métodos , Transplante de Rim/imunologia , Animais , Especificidade de Anticorpos , Azatioprina/uso terapêutico , Terapia Combinada , Ciclosporina/uso terapêutico , Cães , Antígenos Thy-1/imunologia , Fatores de Tempo , Transplante HomólogoAssuntos
Isomerases de Aminoácido/química , Proteínas de Transporte/química , Isomerases de Aminoácido/genética , Isomerases de Aminoácido/fisiologia , Sequência de Aminoácidos , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Transporte/fisiologia , Ciclosporina/metabolismo , Ciclosporina/farmacologia , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Choque Térmico/química , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Técnicas In Vitro , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Peptidilprolil Isomerase , Polienos/metabolismo , Dobramento de Proteína , Homologia de Sequência de Aminoácidos , Sirolimo , Tacrolimo/metabolismo , Tacrolimo/farmacologia , Proteínas de Ligação a TacrolimoAssuntos
Anticorpos Monoclonais/farmacologia , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Imunossupressores/farmacologia , Transplante de Rim/imunologia , Leucócitos/imunologia , Animais , Antígenos de Superfície/imunologia , Cães , Sobrevivência de Enxerto/imunologia , Glicoproteínas de Membrana/imunologia , Ratos , Antígenos Thy-1 , Transplante Homólogo/imunologiaAssuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Transplante de Coração/imunologia , Terapia de Imunossupressão/métodos , Transplante Heterólogo/imunologia , Animais , Cricetinae , Sobrevivência de Enxerto/imunologia , Mesocricetus , Camundongos , Camundongos Endogâmicos CBA , Ratos , Ratos Endogâmicos , Transplante de Pele/imunologiaRESUMO
Liver allografts in pigs and in rats elicit a substantial cellular immune response that can resolve spontaneously with the induction of donor-specific systemic tolerance. Self-limiting interactions between host and donor (graft)-derived leukocytes may be the basis for tolerogenesis. We have attempted to reproduce this effect of liver grafting in pigs by peroperative infusion of donor leukocytes into kidney graft recipients given an interrupted short course of CsA designed to promote donor leukocyte survival and interaction with host cells. This protocol can secure long-term kidney graft survival resistant to challenge by donor skin grafting. Donor skin is, however, rejected, but more slowly than third-party skin, indicating a degree of systemic specific unresponsiveness in these long-term kidney graft recipients.
Assuntos
Ciclosporina/uso terapêutico , Transplante de Rim/imunologia , Animais , Feminino , Sobrevivência de Enxerto , Terapia de Imunossupressão/métodos , Teste de Cultura Mista de Linfócitos , Transplante de Pele/imunologia , Baço/imunologia , SuínosRESUMO
A state of tolerance to MHC mismatched allografts can be generated in rodents by treatment with CD4 and CD8 monoclonal antibodies (mAb). In order to transpose this type of therapy to large animals and ultimately to the clinic, a suitable model is required. To this end we have generated a series of mAb to the canine CD4, CD8, and Thy-1 antigens and have tested their ability to prevent rejection of renal allografts. Donor-recipient pairs were selected from a colony of mongrel dogs in which untreated rejection of two haplotype-mismatched kidneys occurred by day 7 (defined as a serum creatinine > 300 mumol/l). Therapy with either the CD4 or the CD8 mAb, using no other immunosuppression, did not prolong graft survival. Depletion of T cells by a Thy-1 mAb prior to surgery only extended graft survival to day 9. However, treating with combinations of mAb up to day 10 (CD4 plus Thy-1; CD4 plus CD8; or CD4 plus CD8 plus Thy-1) prolonged renal allograft function up to 25 days. Combination of the triple mAb therapy with a sub-therapeutic immunosuppressive drug regimen (cyclosporin A plus azathioprine that alone gave a median survival of 15 days) favored survival to a median of 38 days. This protocol also inhibited the antiglobulin response that had curtailed the effects of mAb treatment, opening the way to more extended, and potentially tolerizing, mAb plus drug regimens.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos de Superfície/imunologia , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Cães/imunologia , Rejeição de Enxerto/prevenção & controle , Terapia de Imunossupressão/métodos , Transplante de Rim/imunologia , Glicoproteínas de Membrana/imunologia , Animais , Anticorpos Monoclonais/imunologia , Ciclosporina/uso terapêutico , Feminino , Imunossupressores/uso terapêutico , Depleção Linfocítica , Masculino , Complicações Pós-Operatórias , Ratos , Linfócitos T , Antígenos Thy-1 , Zidovudina/uso terapêuticoRESUMO
Therapy with CD4 and CD8 monoclonal antibodies was evaluated in dogs which received double-haplotype MHC-mismatched renal allografts. Neither CD4 nor CD8 monoclonal antibodies given alone prolonged allografts survival (creatinine > or = 300 micromol/l) beyond 7 days. However, combined therapy with CD4 and CD8 antibodies given up to day 10 did prolong allograft survival to a median of 14 days. A longer (21 day) course of CD4 and CD8 antibodies did not extend allograft survival further. The effect of prolonged antibody therapy was restricted by the occurrence of both an antiglobulin response and an anaphylactoid reaction to the monoclonal antibody preparation. When the CD4 and CD8 antibodies were combined with a pan-T-cell-depleting Thy-1 antibody, the survival of double-haplotype mismatched allografts was further prolonged (median 16 days). The median survival of single-haplotype mismatched renal allografts on this triple therapy was 21 days, with one surviving to day 36.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígenos CD4/imunologia , Antígenos CD8/imunologia , Transplante de Rim/imunologia , Anafilaxia , Animais , Anticorpos Monoclonais/toxicidade , Cães , Teste de Histocompatibilidade , Terapia de Imunossupressão , Complexo Principal de Histocompatibilidade , Antígenos Thy-1/imunologia , Transplante HomólogoRESUMO
The value of CD4 and CD8 monoclonal antibody therapy in tolerance induction has been demonstrated in rodent transplant models. In this paper the immunosuppressive potential of CD4 and CD8 monoclonal antibodies for dog renal allografts was evaluated as a preliminary to tolerogenic studies in this large animal model. Monoclonal antibodies were given for a maximum of 10 days after transplantation. Therapy was stopped prematurely following adverse reactions associated with the recipient developing an antibody response against the foreign (rat) therapeutic monoclonal antibody. Blood trough levels of CD4 and CD8 antibodies indicated that saturating doses were achieved. Although neither CD4 nor CD8 alone prolonged allograft survival (rejection by day 7), combination of CD4 and CD8 antibodies resulted in good graft function for a median of 14 days. The effect of removing circulating T lymphocytes was also assessed using a lytic Thy-1 monoclonal antibody. Alone Thy-1 had little effect but, when combined with CD4, the median allograft survival time was increased to 15.5 days. Reduction of the number of circulating T lymphocytes appears complementary to blockade of CD4 for immunosuppression, while blockade of CD4 combined with removal of CD8 also favours allograft survival.