RESUMO
Adult T-cell leukemia/lymphoma (ATLL) patients have an extremely poor prognosis, partly due to their immunosuppressive state. The majority of ATLL patients have leukemic cells with phenotype similar to Tregs, prompting suggestions that ATLL cells themselves have immunosuppressive functions. In this study, we detected CD39 expression on ATLL cells, particularly frequent on aggressive subtypes. CD39 and CD73 convert extracellular adenosine triphosphate (ATP) into adenosine, a key player in Tregs' immunosuppression. In vitro culture, both CD39+ ATLL cells and normal Tregs converted rapidly extracellular ATP to AMP, which was disturbed by CD39 inhibitors, and was negated in the CD39 knockout MJ cell line. The proliferation of cocultured CD4+/CD8+ normal T cells was suppressed by CD39+ MJ cells, but not by CD39 knockout MJ cells. Supplemented ATP was exhausted by an EG7-OVA T-cell line with stable CD39 induction, but not by mock. When these cell lines were subcutaneously transplanted into murine flanks, Poly(I:C) peritoneal administration reduced tumor size to 1/3 in mock-transplanted tumors, but not in CD39 induced tumors. Overall, we found that ATLL cells express CD39 at a high rate, and our results suggest that this helps ATLL cells escape antitumor immunity through the extracellular ATPDase-Adenosine cascade. These findings will guide future clinical strategies for ATLL treatment.
Assuntos
Antígenos CD/genética , Apirase/genética , Regulação Leucêmica da Expressão Gênica , Tolerância Imunológica/genética , Imunomodulação/genética , Leucemia-Linfoma de Células T do Adulto/genética , Leucemia-Linfoma de Células T do Adulto/imunologia , Trifosfato de Adenosina/metabolismo , Animais , Antígenos CD/metabolismo , Apirase/metabolismo , Biomarcadores , Linhagem Celular Tumoral , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Xenoenxertos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Imunofenotipagem , Leucemia-Linfoma de Células T do Adulto/diagnóstico , Leucemia-Linfoma de Células T do Adulto/metabolismo , Camundongos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologiaRESUMO
Tyrosine kinase-2 (Tyk2), a member of the Jak family of kinases, mediates the signals triggered by various cytokines, including type I IFNs, IL-12, and IL-23. In the current study, we investigated the in vivo involvement of Tyk2 in several IL-12/Th1- and IL-23/Th17-mediated models of experimental diseases, including methylated BSA injection-induced footpad thickness, imiquimod-induced psoriasis-like skin inflammation, and dextran sulfate sodium- or 2,4,6-trinitrobenzene sulfonic acid-induced colitis. In these disease models, Tyk2 deficiency influenced the phenotypes in immunity and/or inflammation. Our findings demonstrate a somewhat broader contribution of Tyk2 to immune systems than previously expected and suggest that Tyk2 may represent an important candidate for drug development by targeting both the IL-12/Th1 and IL-23/Th17 axes.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Interleucina-12/fisiologia , Interleucina-23/fisiologia , TYK2 Quinase/fisiologia , Células Th1/enzimologia , Células Th1/imunologia , Células Th17/enzimologia , Células Th17/imunologia , Adjuvantes Imunológicos/toxicidade , Aminoquinolinas/toxicidade , Animais , Diferenciação Celular/genética , Colite/induzido quimicamente , Colite/enzimologia , Colite/imunologia , Sulfato de Dextrana/administração & dosagem , Hipersensibilidade Tardia/enzimologia , Hipersensibilidade Tardia/imunologia , Imiquimode , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Psoríase/induzido quimicamente , Psoríase/enzimologia , Psoríase/imunologia , TYK2 Quinase/deficiência , TYK2 Quinase/genética , Células Th1/citologia , Células Th17/citologia , Ácido Trinitrobenzenossulfônico/administração & dosagemRESUMO
OBJECTIVES: To characterize and evaluate the validity of a novel coculture system for studying human B-lymphocyte developmental biology. MATERIALS AND METHODS: We developed a long-term culture system to produce B lymphocytes from human CD34(+) cells purified from umbilical cord blood using human mesenchymal stem cells (hMSC) as stroma. We evaluated the effects of several low molecular weight inhibitors, recombinant proteins, and neutralizing antibodies (Abs) as potential regulators of B-lymphocyte development. RESULTS: Our cocultures of 2000 CD34(+) cells in the presence of stem cell factor and Flt3-ligand produced 1-5 x 10(5) CD10(+) cells after 4 weeks of culture. Surface IgM(+) immature B cells began to appear after 4 weeks. We evaluated the negative-regulatory effects of the transforming growth factor (TGF)-beta superfamily on human B lymphopoiesis, and found that adding an anti-activin A antibody enhanced generation of CD10(+) cells two- to three-fold. As well, the proportion of CD10(+) cells in the generated cells increased markedly, indicating that activin A downregulated B lymphopoiesis more efficiently than myelopoiesis. Addition of TGF-beta1 suppressed B-lymphocyte production by 20% to 30%, while addition of an anti-bone morphogenetic protein (BMP)-4 antibody or recombinant BMP-4 had no effect. Therefore, the strength of ability to suppress human B lymphopoiesis seemed to be activin A > TGF-beta1 > BMP-4. None of these three factors influenced the emergence of IgM(+) cells. CONCLUSIONS: hMSC coculture supported human B lymphopoiesis. Activin A selectively suppressed B lymphocyte production.