RESUMO
Stopping long-term nucleos(t)ide analogue therapy increases hepatitis B virus (HBV) surface antigen (HBsAg) loss rates in HBV e antigen (HBeAg)-negative patients. Viral rebound may induce immune responses facilitating functional cure. We analyzed which factors are associated with timing of virological relapse in 220 Asian HBeAg-negative patients from the prospective ABX203 vaccine study. Unexpectedly, only the type of antiviral therapy was significantly associated with early virological relapse, defined as an HBV DNA load of >2000 IU/mL until week 12, and relapse occurred earlier in patients treated with tenofovir versus those treated with entecavir (median time, 6 vs 24 weeks; P < .0001). This should be considered for future trials and monitoring of patients after treatment discontinuation.
Assuntos
Antivirais/uso terapêutico , Guanina/análogos & derivados , Antígenos E da Hepatite B/genética , Vírus da Hepatite B/efeitos dos fármacos , Hepatite B Crônica/tratamento farmacológico , Tenofovir/uso terapêutico , Adulto , Idoso , DNA Viral/genética , Feminino , Guanina/uso terapêutico , Vírus da Hepatite B/genética , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Resultado do Tratamento , Adulto JovemRESUMO
The p28 subunit of the composite cytokine IL-27 comprises a polyglutamic acid domain, which is unique among type I cytokines. This domain is very similar to the acidic domain known to confer hydroxyapatite (HA)-binding properties and bone tropism to bone sialoprotein. We observed IL-27 binding to HA, in accordance with previous studies reporting successful p28 HA chromatography. The IL-27 polyglutamic acid domain is located in a flexible inter-α helix loop, and HA-bound IL-27 retained biological activity. Using IL-27 alanine mutants, we observed that the p28 polyglutamic acid domain confers HA- and bone-binding properties to IL-27 in vitro and bone tropism in vivo. Because IL-27 is a potent regulator of cells residing in endosteal bone marrow niches such as osteoclasts, T regulatory, memory T, plasma, and stem cells, this specific property could be beneficial for therapeutic applications. IL-27 has potent antitumoral and antiosteoclastogenic activities. It could therefore also be useful for therapies targeting hematologic cancer or solid tumors metastasis with bone tropism. Furthermore, these observations suggest that polyglutamic motifs could be grafted onto other type I cytokine inter-α helix loops to modify their pharmacological properties.
Assuntos
Medula Óssea/química , Durapatita/química , Interleucinas/metabolismo , Ácido Poliglutâmico/química , Motivos de Aminoácidos/imunologia , Animais , Medula Óssea/imunologia , Medula Óssea/metabolismo , Linfócitos T CD8-Positivos/química , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/transplante , Células Cultivadas , Durapatita/metabolismo , Feminino , Humanos , Interleucinas/genética , Interleucinas/uso terapêutico , Camundongos , Camundongos Endogâmicos C57BL , Osteoclastos/imunologia , Osteoclastos/metabolismo , Ácido Poliglutâmico/genética , Ácido Poliglutâmico/uso terapêutico , Ligação Proteica/imunologia , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT3/metabolismo , Células Estromais/imunologia , Células Estromais/metabolismoRESUMO
IL-27 is an APC-derived IL-6/IL-12 family composite cytokine with multiple functions such as regulation of Th1, Th17, and regulatory T cell differentiation, B cell proliferation, and Ig class switching. The IL-27 complex is formed by the association of the cytokine p28 with the soluble cytokine receptor EBV-induced gene 3 (EBI3). The IL-27 cytokine and soluble receptor subunits p28 and EBI3 can be secreted independently. The p28 subunit has been shown to have IL-27-independent biological activities. We previously demonstrated that p28 can form an alternative composite cytokine with the EBI3 homolog cytokine-like factor 1 (CLF; CRLF1). p28/CLF modulates NK cell activity and CD4 T cell cytokine production in vitro. In this study we used IL-6-dependent plasmacytoma cell line B9 and CD4 T cells from IL-27Rα-deficient mice to demonstrate that p28/CLF activates IL-27-unresponsive cells, indicating that p28/CLF and IL-27 signal through different receptors. The observation that p28/CLF, unlike IL-27, sustains B9 plasmacytoma cell proliferation prompted us to investigate the effects of p28/CLF on mouse B cells. We observed that p28/CLF induces IgM, IgG2c, and IgG1 production and plasma cell differentiation. p28/CLF therefore has the potential to contribute to B and plasma cell function, differentiation, and proliferation in normal and pathological conditions such as Castelman's disease and multiple myeloma.
Assuntos
Linfócitos B/citologia , Interleucinas/imunologia , Linfopoese/fisiologia , Plasmócitos/citologia , Animais , Linfócitos B/imunologia , Divisão Celular , Linhagem Celular , Feminino , Imunoglobulinas/biossíntese , Interleucinas/genética , Janus Quinases/fisiologia , Lipopolissacarídeos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosforilação , Plasmócitos/imunologia , Processamento de Proteína Pós-Traducional , Receptores de Citocinas/deficiência , Receptores de Citocinas/genética , Receptores de Interleucina , Proteínas Recombinantes de Fusão/imunologia , Fatores de Transcrição STAT/fisiologia , Transdução de Sinais , Células Th2/imunologia , TransfecçãoRESUMO
BACKGROUND: IL-6 is a pleiotropic cytokine which emerged recently as a key regulator of CD4 T cell function. IL-6 alone or in combination with other cytokines promotes T helper 1, T helper 17 and T follicular helper cell differentiation whilst inhibiting the induction of regulatory T cell generation. IL-6 activates multiple pathways among which JAK/STAT3 is the most clearly validated in the control of CD4 T helper differentiation. Activation of STAT5 by cytokines such as IL-2 can counteract IL-6-induced T helper 17 and T follicular helper cell differentiation and promote the induction of regulatory T cell generation. STAT5 and STAT3 are known to compete for promoter binding sites in CD4 T cells and the two transcription factors are believed to have opposite functions in the control of CD4 T cell differentiation. METHODS: We analyzed IL-6-induced STAT1, 3 and 5 activation by flow cytometry (phosflow) in mouse mononuclear cells and its effect on the level of the mRNA coding for cytokine-inducible SH2-containing protein (CIS). RESULTS: The results show that IL-6 also induces STAT5 activation in both CD4 and CD8 T as well as NK cells. Analysis of STAT5 phosphorylation in CD4 T cells indicates that it is transient and requires higher cytokine concentrations than that of STAT3. CD4 T cell stimulation with IL-6 induces the synthesis of CIS, which is encoded by a gene known to be regulated by STAT5. CONCLUSIONS: Thus, IL-6 at concentrations corresponding to levels observed in the serum during inflammation may activate, in CD4 T cells, a STAT5-negative feedback loop which alters the balance between STAT3-dependent pro-inflammatory helper T cells and STAT5-induced T regulatory cells. STAT5 activation may modulate the differentiation of T helper cells through attenuation of TGF-ß stability and production. Since STAT5 is directly activated by Janus kinases, therapeutic approaches designed to inhibit STAT3 activation or to recruit STAT3 phosphatases may be useful in altering the balance of activated STAT3 and STAT5 in favor a profile that would be beneficial in pathologies involving IL-6.
Assuntos
Interleucina-6/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Fator de Transcrição STAT5/metabolismo , Linfócitos T/metabolismo , Animais , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/metabolismo , Proliferação de Células/efeitos dos fármacos , Feminino , Interleucina-6/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/efeitos dos fármacos , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT3/metabolismo , Proteínas Supressoras da Sinalização de Citocina/metabolismo , Linfócitos T/efeitos dos fármacosRESUMO
Ciliary neurotrophic factor (CNTF) and cardiotrophin-like cytokine (CLC) are two cytokines with neurotrophic and immunomodulatory activities. CNTF is a cytoplasmic factor believed to be released upon cellular damage, while CLC requires interaction with a soluble cytokine receptor, cytokine-like factor 1 (CLF), to be efficiently secreted. Both cytokines activate a receptor complex comprising the cytokine binding CNTF receptor α (CNTFRα) and two signaling chains namely, leukemia inhibitory factor receptor ß (LIFRß) and gp130. Human CNTF can recruit and activate an alternative receptor in which CNTFRα is substituted by IL-6Rα. As both CNTF and CLC have immune-regulatory activities in mice, we compared their ability to recruit mouse receptors comprising both gp130 and LIFRß signaling chains and either IL-6Rα or IL-11Rα which, unlike CNTFRα, are expressed by immune cells. Our results indicate that 1) mouse CNTF, like its human homologue, can activate cells expressing gp130/LIFRß with either CNTFRα or IL-6Rα and, 2) CLC/CLF is more restricted in its specificity in that it activates only the tripartite CNTFR. Several gp130 signaling cytokines influence T helper cell differentiation. We therefore investigated the effect of CNTF on CD4 T cell cytokine production. We observed that CNTF increased the number of IFN-γ producing CD4 T cells. As IFN-γ is considered a mediator of the therapeutic effect of IFN-ß in multiple sclerosis, induction of IFN-γ by CNTF may contribute to the beneficial immunomodulatory effect of CNTF in mouse multiple sclerosis models. Together, our results indicate that CNTF activates the same tripartite receptors in mouse and human cells and further validate rodent models for pre-clinical investigation of CNTF and CNTF derivatives. Furthermore, CNTF and CLC/CLF differ in their receptor specificities. The receptor α chain involved in the immunomodulatory effects of CLC/CLF remains to be identified.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Subunidade alfa do Receptor do Fator Neutrófico Ciliar/metabolismo , Fator Neurotrófico Ciliar/metabolismo , Citocinas/metabolismo , Receptores de Citocinas/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Receptor gp130 de Citocina/metabolismo , Humanos , Interferon gama/biossíntese , Subunidade alfa de Receptor de Interleucina-11/metabolismo , Subunidade alfa de Receptor de Fator Inibidor de Leucemia/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Interleucina-6/metabolismo , Transdução de Sinais , Linfócitos T Auxiliares-Indutores/metabolismoRESUMO
IL-27 is formed by the association of a cytokine subunit, p28, with the soluble cytokine receptor EBV-induced gene 3 (EBI3). The IL-27R comprises gp130 and WSX-1. The marked difference between EBI3(-/-) and WSX-1(-/-) mice suggests that p28 has functions independent of EBI3. We have identified an alternative secreted complex formed by p28 and the soluble cytokine receptor cytokine-like factor 1 (CLF). Like IL-27, p28/CLF is produced by dendritic cells and is biologically active on human NK cells, increasing IL-12- and IL-2-induced IFN-gamma production and activation marker expression. Experiments with Ba/F3 transfectants indicate that p28/CLF activates cells expressing IL-6Ralpha in addition to the IL-27R subunits. When tested on CD4 and CD8 T cells, p28/CLF induces IL-6Ralpha-dependent STAT1 and STAT3 phosphorylation. Furthermore, p28/CLF inhibits CD4 T cell proliferation and induces IL-17 and IL-10 secretion. These results indicate that p28/CLF may participate in the regulation of NK and T cell functions by dendritic cells. The p28/CLF complex engages IL-6R and may therefore be useful for therapeutic applications targeting cells expressing this receptor. Blocking IL-6R using humanized mAbs such as tocilizumab has been shown to be beneficial in pathologies like rheumatoid arthritis and juvenile idiopathic arthritis. The identification of a new IL-6R ligand is therefore important for a complete understanding of the mechanism of action of this emerging class of immunosuppressors.
Assuntos
Interleucinas/metabolismo , Células Matadoras Naturais/imunologia , Subunidades Proteicas/metabolismo , Receptores de Citocinas/metabolismo , Receptores de Interleucina-6/fisiologia , Transdução de Sinais/imunologia , Linfócitos T/imunologia , Animais , Proteínas de Transporte/biossíntese , Linhagem Celular , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Glutationa Transferase/biossíntese , Humanos , Interleucinas/biossíntese , Interleucinas/fisiologia , Células Matadoras Naturais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica/imunologia , Subunidades Proteicas/fisiologia , Receptores de Citocinas/biossíntese , Receptores de Citocinas/fisiologia , Linfócitos T/metabolismoRESUMO
Immunization routes and number of doses remain largely unexplored in therapeutic vaccination. The aim of the present work is to evaluate their impact on immune responses in naïve and hepatitis B virus (HBV)-carrier mouse models following immunization with a non-adjuvanted recombinant vaccine comprising the hepatitis B surface (HBsAg) and core (HBcAg) antigens. Mice were immunized either by intranasal (i.n.), subcutaneous (s.c.) or simultaneous (i.n. + s.c.) routes. Humoral immunity was detected in all the animal models with the induction of a potent antibody (Ab) response against HBcAg, which was stronger than the anti-HBs response. In the HBV-carrier mouse model, the anti-HBs response was predominantly subtype-specific and preferentially induced by the i.n. route. However, the Ab titers were not sufficient to clear the high concentration of HBsAg present in the sera of these mice. The i.n. route was the most efficacious at inducing cellular immune responses, in particular CD4+ T cells. In naïve mice, cellular responses in spleen were strong and mainly due to CD4+ T cells whereas the CD8+ T-cell response was low. In HBV-carrier mice, high frequencies of HBs-specific CD4+ T cells secreting interferon (IFN)-γ, interleukin (IL)-2 and tumor necrosis factor (TNF)-α were found in liver only after i.n. immunization. Increased frequencies of CD4+ T cells expressing the integrin CD49a in liver suggest a role of nasal route in the cellular homing process. Multiple dose schedules appear to be a prerequisite for protein-based immunization in order to overcome immunotolerance in HBV-carrier mice. These findings provide new avenues for further preclinical and clinical development.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Portador Sadio/terapia , Vacinas contra Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Hepatite B/terapia , Fígado/patologia , Administração Intranasal , Animais , Modelos Animais de Doenças , Anticorpos Anti-Hepatite B/sangue , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Vacinas contra Hepatite B/administração & dosagem , Injeções Subcutâneas , Camundongos , Baço/imunologia , Resultado do Tratamento , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologiaRESUMO
Dendritic cells play a central role in the initiation of the immune response as they are the only antigen-presenting cells able to prime naive T cells. This makes the dendritic cells the vector of choice to use as a cell-based vaccine in immunotherapy. Although there are several strategies to deliver antigen to dendritic cells, the ones transfected with mRNA coding for tumor or viral antigens are able to induce potent antigen specific T-cell responses directed against multiple epitopes. In this review, we report several advances made in the field of anti-tumoral and anti-HIV immunotherapy using mRNA-transfected dendritic cells-based approaches.
Assuntos
Células Dendríticas/imunologia , Imunoterapia Ativa , RNA Mensageiro/genética , Animais , Apresentação de Antígeno , Antígenos CD/análise , Antígenos de Neoplasias/genética , Antígenos Virais/genética , Células Cultivadas/imunologia , Células Cultivadas/metabolismo , Ensaios Clínicos Fase I como Assunto , Células Dendríticas/classificação , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Infecções por HIV/terapia , Humanos , Ativação Linfocitária , Camundongos , Células Mieloides/citologia , Neoplasias/terapia , RNA Neoplásico/genética , RNA Viral/genética , Linfócitos T/imunologia , TransfecçãoRESUMO
We have assessed the immune-regulatory and adjuvant activities of a synthetic glycolipid, ABX196, a novel analog of the parental compound α-GalCer. As expected, ABX196 demonstrated a measurable and significant adjuvant effect in mice and monkeys with no appreciable toxicity at the doses used to promote immune responses. We performed a phase I/II dose escalation study of ABX196 in healthy volunteers, with the objectives to evaluate its safety profile, as well as its ability to be utilized as an adjuvant in the context of a prophylactic vaccine against hepatitis B. ABX196 was administered at three doses: 0.2, 0.4, and 2.0µg, in 44 subjects. In all the individuals injected with ABX196, peripheral blood NKT cells displayed hallmarks of activation, and 45% of them had measurable circulating IFN-γ 24h after the first administration. More importantly, the addition of ABX196 to the very poorly immunogenic HBs antigen resulted in protective anti-HBs antibody responses in majority of patients, demonstrating the adjuvant properties of ABX196 in human. Further analysis of the cohort of subjects receiving ABX196 with HBs antigen also indicates that a single injection appears sufficient to provide protection. A limited set of adverse events linked to the systemic delivery of ABX196 and access to the liver, is discussed in the context of formulation and the need to limit transport of ABX196 to secondary lymphoid tissues for maximal efficacy (Eudra-CT 2012-001566-15).