RESUMO
The sensing of microbial genetic material by leukocytes often elicits beneficial pro-inflammatory cytokines, but dysregulated responses can cause severe pathogenesis. Genome-wide association studies have linked the gene encoding phospholipase D3 (PLD3) to Alzheimer's disease and have linked PLD4 to rheumatoid arthritis and systemic sclerosis. PLD3 and PLD4 are endolysosomal proteins whose functions are obscure. Here, PLD4-deficient mice were found to have an inflammatory disease, marked by elevated levels of interferon-γ (IFN-γ) and splenomegaly. These phenotypes were traced to altered responsiveness of PLD4-deficient dendritic cells to ligands of the single-stranded DNA sensor TLR9. Macrophages from PLD3-deficient mice also had exaggerated TLR9 responses. Although PLD4 and PLD3 were presumed to be phospholipases, we found that they are 5' exonucleases, probably identical to spleen phosphodiesterase, that break down TLR9 ligands. Mice deficient in both PLD3 and PLD4 developed lethal liver inflammation in early life, which indicates that both enzymes are needed to regulate inflammatory cytokine responses via the degradation of nucleic acids.
Assuntos
Células Dendríticas/fisiologia , Endossomos/metabolismo , Exonucleases/metabolismo , Hepatite/genética , Macrófagos/fisiologia , Glicoproteínas de Membrana/metabolismo , Fosfolipase D/metabolismo , Doença de Alzheimer/genética , Animais , Artrite Reumatoide/genética , DNA de Cadeia Simples/imunologia , Exonucleases/genética , Estudo de Associação Genômica Ampla , Humanos , Interferon gama/metabolismo , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfolipase D/genética , Escleroderma Sistêmico/genética , Transdução de Sinais , Receptor Toll-Like 9/metabolismoRESUMO
Anti-HIV broadly neutralizing antibodies (bNAbs) offer a novel approach to treating, preventing, or curing HIV. Pre-clinical models and clinical trials involving the passive transfer of bNAbs have demonstrated that they can control viremia and potentially serve as alternatives or complement antiretroviral therapy (ART). However, antibody decay, persistent latent reservoirs, and resistance impede bNAb treatment. This review discusses recent advancements and obstacles in applying bNAbs and proposes strategies to enhance their therapeutic potential. These strategies include multi-epitope targeting, antibody half-life extension, combining with current and newer antiretrovirals, and sustained antibody secretion.
Assuntos
Infecções por HIV , HIV-1 , Humanos , Anticorpos Amplamente Neutralizantes/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , Infecções por HIV/tratamento farmacológico , Anticorpos Anti-HIV/uso terapêuticoRESUMO
The evolution of drug-resistant viral strains and anatomical and cellular reservoirs of HIV pose significant clinical challenges to antiretroviral therapy. CCR5 is a coreceptor critical for HIV host cell fusion, and a homozygous 32-bp gene deletion (∆32) leads to its loss of function. Interestingly, an allogeneic HSCT from an HIV-negative ∆32 donor to an HIV-1-infected recipient demonstrated a curative approach by rendering the recipient's blood cells resistant to viral entry. Ex vivo gene editing tools, such as CRISPR/Cas9, hold tremendous promise in generating allogeneic HSC grafts that can potentially replace allogeneic ∆32 HSCTs. Here, we review antiretroviral therapeutic challenges, clinical successes, and failures of allogeneic and allogeneic ∆32 HSCTs, and newer exciting developments within CCR5 editing using CRISPR/Cas9 in the search to cure HIV.
Assuntos
Antirretrovirais , Infecções por HIV , HIV-1 , Humanos , Antirretrovirais/uso terapêutico , Sistemas CRISPR-Cas/genética , Edição de Genes , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Infecções por HIV/terapia , HIV-1/genética , Receptores CCR5/genética , Farmacorresistência Viral/genéticaRESUMO
Here we describe a previously unknown form of inherited immunodeficiency revealed by an N-ethyl-N-nitrosourea-induced mutation called elektra. Mice homozygous for this mutation showed enhanced susceptibility to bacterial and viral infection and diminished numbers of T cells and inflammatory monocytes that failed to proliferate after infection and died via the intrinsic apoptotic pathway in response to diverse proliferative stimuli. They also had a greater proportion of T cells poised to replicate DNA, and their T cells expressed a subset of activation markers, suggestive of a semi-activated state. We positionally ascribe the elektra phenotype to a mutation in the gene encoding Schlafen-2 (Slfn2). Our findings identify a physiological role for Slfn2 in the defense against pathogens through the regulation of quiescence in T cells and monocytes.
Assuntos
Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/imunologia , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Leucócitos Mononucleares/imunologia , Linfócitos T/imunologia , Animais , Apoptose/imunologia , Sequência de Bases , Separação Celular , Citometria de Fluxo , Ativação Linfocitária/imunologia , Camundongos , Camundongos Transgênicos , Mutação , Fenótipo , Transdução de Sinais/imunologiaRESUMO
Progressive phases of multiple sclerosis are associated with inhibited differentiation of the progenitor cell population that generates the mature oligodendrocytes required for remyelination and disease remission. To identify selective inducers of oligodendrocyte differentiation, we performed an image-based screen for myelin basic protein (MBP) expression using primary rat optic-nerve-derived progenitor cells. Here we show that among the most effective compounds identifed was benztropine, which significantly decreases clinical severity in the experimental autoimmune encephalomyelitis (EAE) model of relapsing-remitting multiple sclerosis when administered alone or in combination with approved immunosuppressive treatments for multiple sclerosis. Evidence from a cuprizone-induced model of demyelination, in vitro and in vivo T-cell assays and EAE adoptive transfer experiments indicated that the observed efficacy of this drug results directly from an enhancement of remyelination rather than immune suppression. Pharmacological studies indicate that benztropine functions by a mechanism that involves direct antagonism of M1 and/or M3 muscarinic receptors. These studies should facilitate the development of effective new therapies for the treatment of multiple sclerosis that complement established immunosuppressive approaches.
Assuntos
Benzotropina/uso terapêutico , Encefalomielite Autoimune Experimental/tratamento farmacológico , Modelos Biológicos , Esclerose Múltipla/tratamento farmacológico , Bainha de Mielina/efeitos dos fármacos , Oligodendroglia/efeitos dos fármacos , Regeneração/efeitos dos fármacos , Animais , Antiparkinsonianos/farmacologia , Antiparkinsonianos/uso terapêutico , Benzotropina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Técnicas de Cocultura , Cuprizona/farmacologia , Cuprizona/uso terapêutico , Encefalomielite Autoimune Experimental/induzido quimicamente , Encefalomielite Autoimune Experimental/patologia , Feminino , Cloridrato de Fingolimode , Sistema Imunitário/efeitos dos fármacos , Sistema Imunitário/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/patologia , Proteína Proteolipídica de Mielina/farmacologia , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Nervo Óptico/citologia , Propilenoglicóis/farmacologia , Propilenoglicóis/uso terapêutico , Ratos , Receptor Muscarínico M1/antagonistas & inibidores , Receptor Muscarínico M1/metabolismo , Receptor Muscarínico M3/antagonistas & inibidores , Receptor Muscarínico M3/metabolismo , Recidiva , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Esfingosina/uso terapêutico , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacosRESUMO
Bispecific antibodies, which simultaneously target CD3 on T cells and tumor-associated antigens to recruit cytotoxic T cells to cancer cells, are a promising new approach to the treatment of hormone-refractory prostate cancer. Here we report a site-specific, semisynthetic method for the production of bispecific antibody-like therapeutics in which a derivative of the prostate-specific membrane antigen-binding small molecule DUPA was selectively conjugated to a mutant αCD3 Fab containing the unnatural amino acid, p-acetylphenylalanine, at a defined site. Homogeneous conjugates were generated in excellent yields and had good solubility. The efficacy of the conjugate was optimized by modifying the linker structure, relative binding orientation, and stoichiometry of the ligand. The optimized conjugate showed potent and selective in vitro activity (EC50 ~ 100 pM), good serum half-life, and potent in vivo activity in prophylactic and treatment xenograft mouse models. This semisynthetic approach is likely to be applicable to the generation of additional bispecific agents using drug-like ligands selective for other cell-surface receptors.
Assuntos
Descoberta de Drogas/métodos , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Neoplasias da Próstata/tratamento farmacológico , Animais , Complexo CD3/imunologia , Xenoenxertos/imunologia , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoterapia/métodos , Leucócitos Mononucleares , Masculino , Camundongos , Neoplasias da Próstata/imunologia , Engenharia de ProteínasRESUMO
The development of immunotherapies for multiple myeloma is critical to provide new treatment strategies to combat drug resistance. We report a bispecific antibody against B cell maturation antigen (BiFab-BCMA), which potently and specifically redirects T cells to lyse malignant multiple myeloma cells. BiFab-BCMA lysed target BCMA-positive cell lines up to 20-fold more potently than a CS1-targeting bispecific antibody (BiFab-CS1) developed in an analogous fashion. Further, BiFab-BCMA robustly activated T cells in vitro and mediated rapid tumor regression in an orthotopic xenograft model of multiple myeloma. The in vitro and in vivo activities of BiFab-BCMA are comparable to those of anti-BCMA chimeric antigen receptor T cell therapy (CAR-T-BCMA), for which two clinical trials have recently been initiated. A BCMA-targeted bispecific antibody presents a promising treatment option for multiple myeloma.
Assuntos
Anticorpos Biespecíficos/imunologia , Anticorpos Biespecíficos/uso terapêutico , Antígeno de Maturação de Linfócitos B/imunologia , Mieloma Múltiplo/terapia , Animais , Linhagem Celular Tumoral , Humanos , Imunoterapia , Camundongos SCID , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/patologia , Linfócitos T/imunologia , Linfócitos T/patologiaRESUMO
We have developed a novel antibody-drug conjugate (ADC) that can selectively deliver the Lck inhibitor dasatinib to human T lymphocytes. This ADC is based on a humanized antibody that selectively binds with high affinity to CXCR4, an antigen that is selectively expressed on hematopoietic cells. The resulting dasatinib-antibody conjugate suppresses T-cell-receptor (TCR)-mediated T-cell activation and cytokine expression with low nM EC50 and has minimal effects on cell viability. This ADC may lead to a new class of selective immunosuppressive drugs with improved safety and extend the ADC strategy to the targeted delivery of kinase inhibitors for indications beyond oncology.
Assuntos
Anticorpos/química , Dasatinibe/administração & dosagem , Imunoconjugados/química , Imunossupressores/química , Linfócitos T/efeitos dos fármacos , Dasatinibe/química , Dasatinibe/farmacologia , Células HEK293 , Humanos , Imunoconjugados/administração & dosagem , Imunossupressores/administração & dosagem , Imunossupressores/farmacologia , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/antagonistas & inibidores , Receptores CXCR4/imunologia , Receptores CXCR4/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Trastuzumab/imunologiaRESUMO
IL-7 is known to be vital for T cell homeostasis but has previously been presumed to be dispensable for TCR-induced activation. Here, we show that IL-7 is critical for the initial activation of CD4(+) T cells in that it provides some of the necessary early signaling components, such as activated STAT5 and Akt. Accordingly, short-term in vivo IL-7Rα blockade inhibited the activation and expansion of autoantigen-specific CD4(+) T cells and, when used to treat experimental autoimmune encephalomyelitis (EAE), prevented and ameliorated disease. Our studies demonstrate that IL-7 signaling is a prerequisite for optimal CD4(+) T cell activation and that IL-7R antagonism may be effective in treating CD4(+) T cell-mediated neuroinflammation and other autoimmune inflammatory conditions.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Encefalomielite Autoimune Experimental/imunologia , Interleucina-7/imunologia , Ativação Linfocitária/imunologia , Animais , Linfócitos T CD4-Positivos/metabolismo , Proliferação de Células , Citocinas/imunologia , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/metabolismo , Citometria de Fluxo , Humanos , Interleucina-7/deficiência , Interleucina-7/genética , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Camundongos Transgênicos , Fosforilação/imunologia , Proteínas Proto-Oncogênicas c-akt/imunologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Interleucina-7/imunologia , Receptores de Interleucina-7/metabolismo , Fator de Transcrição STAT2/imunologia , Fator de Transcrição STAT2/metabolismo , Transdução de Sinais/imunologiaRESUMO
Nucleic acid (NA)-sensing TLRs (NA-TLRs) promote the induction of anti-nuclear Abs in systemic lupus erythematosus. However, the extent to which other nonnuclear pathogenic autoantibody specificities that occur in lupus and independently in other autoimmune diseases depend on NA-TLRs, and which immune cells require NA-TLRs in systemic autoimmunity, remains to be determined. Using Unc93b1(3d) lupus-prone mice that lack NA-TLR signaling, we found that all pathogenic nonnuclear autoantibody specificities examined, even anti-RBC, required NA-TLRs. Furthermore, we document that NA-TLRs in B cells were required for the development of antichromatin and rheumatoid factor. These findings support a unifying NA-TLR-mediated mechanism of autoantibody production that has both pathophysiological and therapeutic implications for systemic lupus erythematosus and several other humoral-mediated autoimmune diseases. In particular, our findings suggest that targeting of NA-TLR signaling in B cells alone would be sufficient to specifically block production of a broad diversity of autoantibodies.
Assuntos
Anticorpos Antinucleares/imunologia , Linfócitos B/imunologia , Glicoproteínas de Membrana/imunologia , Ácidos Nucleicos/imunologia , Receptor 7 Toll-Like/imunologia , Receptor Toll-Like 9/imunologia , Animais , Células Produtoras de Anticorpos/imunologia , Autoanticorpos/imunologia , Células da Medula Óssea/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Cromatina/imunologia , Células Dendríticas , Feminino , Síndromes de Imunodeficiência , Lúpus Eritematoso Sistêmico/imunologia , Ativação Linfocitária/imunologia , Macrófagos/imunologia , Proteínas de Membrana Transportadoras/imunologia , Camundongos , Camundongos Endogâmicos NZB , Fator 88 de Diferenciação Mieloide/imunologia , Doenças da Imunodeficiência Primária , Fator Reumatoide/imunologia , Ribonucleoproteínas/imunologia , Transdução de SinaisRESUMO
Four different formats of bispecific antibodies (bsAbs) were generated that consist of anti-Her2 IgG or Fab site-specifically conjugated to anti-CD3 Fab using the genetically encoded noncanonical amino acid. These bsAbs varied in valency or in the presence or absence of an Fc domain. Different valencies did not significantly affect antitumor efficacy, whereas the presence of an Fc domain enhanced cytotoxic activity, but triggered antigen-independent T-cell activation. We show that the bsAbs can efficiently redirect Tâ cells to kill all Her2 expressing cancer cells, including Her2 1+ cancers, both inâ vitro and in rodent xenograft models. This work increases our understanding of the structural features that affect bsAb activity, and underscores the potential of bsAbs as a promising therapeutic option for breast cancer patients with low or heterogeneous Her2 expression.
Assuntos
Anticorpos Biespecíficos/química , Linfócitos T/metabolismo , Animais , Anticorpos Biespecíficos/imunologia , Anticorpos Biespecíficos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Complexo CD3/imunologia , Linhagem Celular Tumoral , Feminino , Humanos , Células Jurkat , Leucócitos Mononucleares/imunologia , Camundongos , Receptor ErbB-2/imunologia , Receptores Fc/química , Receptores Fc/metabolismo , Linfócitos T/imunologia , Trastuzumab/química , Trastuzumab/imunologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The demonstration in humans and mice that nucleic acid-sensing TLRs and type I IFNs are essential disease mediators is a milestone in delineating the mechanisms of lupus pathogenesis. In this study, we show that Ifnb gene deletion does not modify disease progression in NZB mice, thereby strongly implicating IFN-α subtypes as the principal pathogenic effectors. We further document that long-term treatment of male BXSB mice with an anti-IFN-α/ß receptor Ab of mouse origin reduced serologic, cellular, and histologic disease manifestations and extended survival, suggesting that disease acceleration by the Tlr7 gene duplication in this model is mediated by type I IFN signaling. The efficacy of this treatment in BXSB mice was clearly evident when applied early in the disease process, but only partial reductions in some disease characteristics were observed when treatment was initiated at later stages. A transient therapeutic effect was also noted in the MRL-Fas(lpr) model, although overall mortality was unaffected. The combined findings suggest that IFN-α/ß receptor blockade, particularly when started at early disease stages, may be a useful treatment approach for human systemic lupus erythematosus and other autoimmune syndromes.
Assuntos
Anticorpos Monoclonais/administração & dosagem , Autoanticorpos/administração & dosagem , Nefrite Lúpica/imunologia , Nefrite Lúpica/terapia , Receptor de Interferon alfa e beta/imunologia , Animais , Anticorpos Antinucleares/administração & dosagem , Anticorpos Antinucleares/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Autoanticorpos/biossíntese , Autoanticorpos/uso terapêutico , Células Cultivadas , Predisposição Genética para Doença/etiologia , Humanos , Nefrite Lúpica/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos MRL lpr , Camundongos Endogâmicos NZB , Camundongos Knockout , Proteinúria/genética , Proteinúria/imunologia , Proteinúria/terapiaRESUMO
Acute myeloid leukemia (AML), which is the most common acute adult leukemia and the second most common pediatric leukemia, still has a poor prognosis. Human C-type lectin-like molecule-1 (CLL1) is a recently identified myeloid lineage restricted cell surface marker, which is overexpressed in over 90% of AML patient myeloid blasts and in leukemic stem cells. Here, we describe the synthesis of a novel bispecific antibody, αCLL1-αCD3, using the genetically encoded unnatural amino acid, p-acetylphenylalanine. The resulting αCLL1-αCD3 recruits cytotoxic Tâ cells to CLL1 positive cells, and demonstrates potent and selective cytotoxicity against several human AML cell lines and primary AML patient derived cells inâ vitro. Moreover, αCLL1-αCD3 treatment completely eliminates established tumors in an U937 AML cell line xenograft model. These results validate the clinical potential of CLL1 as an AML-specific antigen for the generation of a novel immunotherapeutic for AML.
Assuntos
Anticorpos Biespecíficos/imunologia , Imunoterapia/métodos , Lectinas Tipo C/imunologia , Leucemia Mieloide Aguda/imunologia , Adulto , HumanosRESUMO
A chemically defined anti-CXCR4-auristatin antibody-drug conjugate (ADC) was synthesized that selectively eliminates tumor cells overexpressing the CXCR4 receptor. The unnatural amino acid p-acetylphenylalanine (pAcF) was site-specifically incorporated into an anti-CXCR4 immunoglobulinâ G (IgG) and conjugated to an auristatin through a stable, non-cleavable oxime linkage to afford a chemically homogeneous ADC. The full-length anti-CXCR4 ADC was selectively cytotoxic to CXCR4(+) cancer cells inâ vitro (half maximal effective concentration (EC50 )≈80-100â pM). Moreover, the anti-CXCR4 ADC eliminated pulmonary lesions from human osteosarcoma cells in a lung-seeding tumor model in mice. No significant overt toxicity was observed but there was a modest decrease in the bone-marrow-derived CXCR4(+) cell population. Because CXCR4 is highly expressed in a majority of metastatic cancers, a CXCR4-auristatin ADC may be useful for the treatment of a variety of metastatic malignancies.
Assuntos
Anticorpos Monoclonais/química , Antineoplásicos/química , Imunoconjugados/química , Imunoterapia/métodos , Receptores CXCR4/química , Linhagem Celular Tumoral , HumanosRESUMO
Post-translational protein modifications can play a significant role in immune cell signaling. Recently, we showed that inhibition of transmethylation curtails experimental autoimmune encephalomyelitis, notably by reducing T cell receptor (TCR)-induced activation of CD4(+) T cells. Here, we demonstrate that transmethylation inhibition by a reversible S-adenosyl-l-homocysteine hydrolase inhibitor (DZ2002) led to immunosuppression by reducing TLR-, B cell receptor (BCR)- and TCR-induced activation of immune cells, most likely by blocking NF-κB activity. Moreover, prophylactic treatment with DZ2002 prevented lupus-like disease from developing in both BXSB and MRL-Fas(lpr) mouse models. DZ2002 treatment initiated during active disease significantly improved outcomes in both in vivo models, suggesting methylation inhibition as a novel approach for the treatment of autoimmune/inflammatory diseases.
Assuntos
Adenina/análogos & derivados , Butiratos/uso terapêutico , Imunossupressores/uso terapêutico , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Receptores Toll-Like/imunologia , Adenina/uso terapêutico , Animais , Células Apresentadoras de Antígenos/imunologia , Autoanticorpos/sangue , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Citocinas/sangue , Modelos Animais de Doenças , Feminino , Imunoglobulina G/sangue , Rim/efeitos dos fármacos , Rim/patologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Masculino , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , NF-kappa B/imunologia , Processamento de Proteína Pós-Traducional , Transdução de SinaisRESUMO
The activation of immune cells is mediated by a network of signaling proteins that can undergo post-translational modifications critical for their activity. Methylation of nucleic acids or proteins can have major effects on gene expression as well as protein repertoire diversity and function. Emerging data indicate that indeed many immunologic functions, particularly those of T cells, including thymic education, differentiation and effector function are highly dependent on methylation events. The critical role of methylation in immunocyte biology is further documented by evidence that autoimmune phenomena may be curtailed by methylation inhibitors. Additionally, epigenetic alterations imprinted by methylation can also exert effects on normal and abnormal immune responses. Further work in defining methylation effects in the immune system is likely to lead to a more detailed understanding of the immune system and may point to the development of novel therapeutic approaches.
Assuntos
Autoimunidade/imunologia , Sistema Imunitário/imunologia , Imunidade/imunologia , Linfócitos T/imunologia , Animais , Humanos , Sistema Imunitário/citologia , Sistema Imunitário/metabolismo , Metilação , Modelos Imunológicos , Transdução de Sinais/imunologia , Linfócitos T/citologia , Linfócitos T/metabolismo , Timócitos/citologia , Timócitos/imunologia , Timócitos/metabolismoRESUMO
Using the Unc93b1 3d mutation that selectively abolishes nucleic acid-binding Toll-like receptor (TLR) (TLR3, -7, -9) signaling, we show these endosomal TLRs are required for optimal production of IgG autoAbs, IgM rheumatoid factor, and other clinical parameters of disease in 2 lupus strains, B6-Fas(lpr) and BXSB. Strikingly, treatment with lipid A, an autoAb-inducing TLR4 agonist, could not overcome this requirement. The 3d mutation slightly reduced complete Freund's adjuvant (CFA)-mediated antigen presentation, but did not affect T-independent type 1 or alum-mediated T-dependent humoral responses or TLR-independent IFN production induced by cytoplasmic nucleic acids. These findings suggest that nucleic acid-sensing TLRs might act as an Achilles' heel in susceptible individuals by providing a critical pathway by which relative tolerance for nucleic acid-containing antigens is breached and systemic autoimmunity ensues. Importantly, this helps provide an explanation for the high frequency of anti-nucleic acid Abs in lupus-like systemic autoimmunity.
Assuntos
Anticorpos Antinucleares/imunologia , Endossomos/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Fator Reumatoide/imunologia , Transdução de Sinais/imunologia , Receptores Toll-Like/imunologia , Animais , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Células Dendríticas/citologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Endossomos/efeitos dos fármacos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Lúpus Eritematoso Sistêmico/patologia , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos MRL lpr , Mutação/genética , Ácidos Nucleicos/farmacologia , Picratos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Análise de Sobrevida , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Receptor 4 Toll-Like/imunologiaRESUMO
A recessive phenotype called spin (spontaneous inflammation) was induced by N-ethyl-N-nitrosourea (ENU) mutagenesis in C57BL/6J mice. Homozygotes display chronic inflammatory lesions affecting the feet, salivary glands and lungs, and antichromatin antibodies. They are immunocompetent and show enhanced resistance to infection by Listeria monocytogenes. TLR-induced TNF and IL-1 production are normal in macrophages derived from spin mice. The autoinflammatory phenotype of spin mice is fully suppressed by compound homozygosity for Myd88(poc), Irak4(otiose), and Il1r1-null mutations, but not Ticam1(Lps2), Stat1(m1Btlr), or Tnf-null mutations. Both autoimmune and autoinflammatory phenotypes are suppressed when spin homozygotes are derived into a germ-free environment. The spin phenotype was ascribed to a viable hypomorphic allele of Ptpn6, which encodes the tyrosine phosphatase SHP1, mutated in mice with the classical motheaten alleles me and me-v. Inflammation and autoimmunity caused by SHP1 deficiency are thus conditional. The SHP1-deficient phenotype is driven by microbes, which activate TLR signaling pathways to elicit IL-1 production. IL-1 signaling via MyD88 elicits inflammatory disease.
Assuntos
Doenças Autoimunes/genética , Inflamação/genética , Interleucina-1/imunologia , Listeriose/imunologia , Fator 88 de Diferenciação Mieloide/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Alelos , Animais , Doenças Autoimunes/imunologia , Doenças Autoimunes/microbiologia , Autoimunidade/genética , Etilnitrosoureia/farmacologia , Homozigoto , Inflamação/imunologia , Inflamação/microbiologia , Interleucina-1/genética , Quinases Associadas a Receptores de Interleucina-1/genética , Quinases Associadas a Receptores de Interleucina-1/imunologia , Camundongos , Camundongos Mutantes , Mutagênese , Mutação , Fator 88 de Diferenciação Mieloide/genética , Receptores de Interleucina-1/imunologia , Receptores Toll-Like/imunologiaRESUMO
A characteristic feature of systemic lupus erythematosus is the accumulation of activated/memory T and B cells. These G0/G1-arrested cells express high levels of cyclin-dependent kinase inhibitors such as p21, are resistant to proliferation and apoptosis, and produce large amounts of proinflammatory cytokines. Herein, we show that ablation of p21 in lupus-prone mice allows these cells to reenter the cell cycle and undergo apoptosis, leading to autoimmune disease reduction. Absence of p21 resulted in enhanced Fas/FasL-mediated activation-induced T cell death, increased activation of procaspases 8 and 3, and loss of mitochondrial transmembrane potential. Increased apoptosis was also associated with p53 up-regulation and a modest shift in the ratio of Bax/Bcl-2 toward the proapoptotic Bax. Proliferation and apoptosis of B cells were also increased in p21-/- lupus mice. Thus, modulation of the cell cycle pathway may be a novel approach to reduce apoptosis-resistant pathogenic lymphocytes and to ameliorate systemic autoimmunity.
Assuntos
Doenças Autoimunes/imunologia , Autoimunidade/imunologia , Ciclinas/imunologia , Memória Imunológica/imunologia , Linfócitos T/imunologia , Animais , Doenças Autoimunes/prevenção & controle , Linfócitos B/imunologia , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/deficiência , Ciclinas/genética , Modelos Animais de Doenças , Citometria de Fluxo , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/prevenção & controle , Camundongos , Camundongos KnockoutRESUMO
We have demonstrated that murine thymic dendritic cells (DCs) isolated from donor mice have the capability to home to thymi of fully allogeneic recipients after intravenous injections, where they induce T cell deletions and prolong donor-strain airway and skin graft survival. In contrast, infused splenic DCs immigrated poorly to thymi, and did not affect graft survival. These findings suggest that preferential homing may be an important mechanistic difference among subpopulations of DCs that mediate immune functions and illustrate a novel methodology that could have utility for induction of specific immunologic nonreactivity to allografts, or other disease-associated antigens.