RESUMO
Functionally diverse T cell populations interact to maintain homeostasis of the immune system. We found that human and mouse antigen-activated T cells with high expression of the lymphocyte surface marker CD52 suppressed other T cells. CD52(hi)CD4(+) T cells were distinct from CD4(+)CD25(+)Foxp3(+) regulatory T cells. Their suppression was mediated by soluble CD52 released by phospholipase C. Soluble CD52 bound to the inhibitory receptor Siglec-10 and impaired phosphorylation of the T cell receptor-associated kinases Lck and Zap70 and T cell activation. Humans with type 1 diabetes had a lower frequency and diminished function of CD52(hi)CD4(+) T cells responsive to the autoantigen GAD65. In diabetes-prone mice of the nonobese diabetic (NOD) strain, transfer of lymphocyte populations depleted of CD52(hi) cells resulted in a substantially accelerated onset of diabetes. Our studies identify a ligand-receptor mechanism of T cell regulation that may protect humans and mice from autoimmune disease.
Assuntos
Antígenos CD/imunologia , Antígenos de Neoplasias/imunologia , Linfócitos T CD4-Positivos/imunologia , Diabetes Mellitus Tipo 1/imunologia , Glicoproteínas/imunologia , Ativação Linfocitária/imunologia , Lectinas Semelhantes a Imunoglobulina de Ligação ao Ácido Siálico/imunologia , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Antígenos CD/genética , Antígenos de Neoplasias/genética , Autoantígenos/imunologia , Antígeno CD52 , Feminino , Citometria de Fluxo , Glicoproteínas/genética , Homeostase/imunologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Fosforilação/imunologia , RNA Mensageiro/química , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteína-Tirosina Quinase ZAP-70/imunologiaRESUMO
Autoantigen-specific regulatory T cells (Treg) are a potential cell therapy for human autoimmune disease, provided they could be generated in adequate numbers and with stable function. To this end, we determined the feasibility of cloning and expanding human CD4(+) Treg specific for the type 1 diabetes autoantigens, GAD65 and proinsulin. Blood CD4(+) cells stimulated to divide in response to GAD65 (in three healthy individuals) or proinsulin (in one type 1 diabetic) were flow sorted into single cells and cultured on feeder cells in the presence of anti-CD3 monoclonal antibody, IL-2 and IL-4. Clones were expanded over 4-6 weeks and screened for autoantigen-dependent suppression of tetanus toxoid-specific T-cell proliferation. Suppression by Treg clones was then confirmed against autoantigen-specific non-Treg clones. Of a total of 447 clones generated, 98 (21.9%) had autoantigen-dependent suppressor function. Treg clones were anergic but proliferated to autoantigen after addition of IL-2 or in co-culture with stimulated bulk T cells, without loss of suppressor function. Treg clones were stored over liquid N(2), thawed and further expanded over 12 days, whereupon they exhibited decreased suppressor function. Expansion of Treg clones overall was in the order 107-108-fold. Treg clones were not distinguished by markers of conventional CD4(+)CD25(+) Treg and suppressed independently of cell-cell contact but not via known soluble suppressor factors. This study demonstrates that autoantigen-specific CD4(+) Treg clones with potential application as a cell therapy for autoimmune disease can be generated and expanded from human blood.
Assuntos
Autoantígenos/imunologia , Técnicas de Cultura de Células/métodos , Ilhotas Pancreáticas/imunologia , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Separação Celular , Células Clonais/imunologia , Citometria de Fluxo , Glutamato Descarboxilase/imunologia , Humanos , Imunofenotipagem , Ativação Linfocitária/imunologia , Masculino , Proinsulina/imunologia , Adulto JovemRESUMO
BACKGROUND/AIMS: Protein induced by vitamin K absence or antagonist-II (PIVKA-II), also known as des-carboxyprothrombin (DCP), can be used as an alternative tool to alpha-fetoprotein (AFP) for surveillance of hepatocellular carcinoma (HCC). The aims of the present study were to compare PIVKA-II levels between the patients with HCC and patients with non-HCC chronic liver disease, to evaluate the correlation of PIVKA-II and AFP in HCC patients, and finally to estimate the optimal cut-off value for PIVKA-II for the diagnosis of HCC with using the receiver operating characteristic (ROC) curve. METHODS: A total of 227 consecutive patients with HCC (n=42) or chronic liver disease (n=185) were enrolled in this study. HCC was diagnosed histologically or by imaging such as computed tomography, magnetic resonance imaging or angiography. The serum PIVKA-II and AFP levels were measured by electrochemiluminoimmunoassay with using the Haicatch PIVKA-II kit and by immunoradiometric assay, respectively. RESULTS: The PIVKA-II level in the HCC patients was significantly higher than the non-HCC chronic liver disease patients (903.0+/-1156.7 vs. 111.7+/-211.0 mAU/ mL, respectively, P<0.01). PIVKA-II and AFP showed a statistical correlation in HCC patients (r=0.46, P<0.01). The sensitivity and specificity of PIVKA-II for the diagnosis of HCC were 66.7% and 74.1%, respectively, and when tasted together with AFP, the sensitivity was increased by 85.7%. For the ROC curve of PIVKA-II in HCC patients, the specificity of a 250 mAU/mL level of PIVKA-II was 95%. CONCLUSIONS: PIVKA-II was as useful surveillance tool for differentiating HCC from chronic liver disease, and a PIVKA-II value of 250 mAU/ mL was proposed as a significant cut-off value for diagnosis of hepatocellular carcinoma.
Assuntos
Biomarcadores Tumorais/sangue , Biomarcadores/sangue , Carcinoma Hepatocelular/diagnóstico , Neoplasias Hepáticas/diagnóstico , Precursores de Proteínas/sangue , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Protrombina , Curva ROC , alfa-Fetoproteínas/análiseRESUMO
Genes for peripheral tissue-restricted self-antigens are expressed in thymic and hematopoietic cells. In thymic medullary epithelial cells, self-antigen expression imposes selection on developing autoreactive T cells and regulates susceptibility to autoimmune disease in mouse models. Less is known about the role of self-antigen expression by hematopoietic cells. Here we demonstrate that one of the endocrine self-antigens expressed by human blood myeloid cells, proinsulin, is encoded by an RNA splice variant. The surface expression of immunoreactive proinsulin was significantly decreased after transfection of monocytes with small interfering RNA to proinsulin. Furthermore, analogous to proinsulin transcripts in the thymus, the abundance of the proinsulin RNA splice variant in blood cells corresponded with the length of the variable number of tandem repeats 5' of the proinsulin gene, known to be associated with type 1 diabetes susceptibility. Self-antigen expression by peripheral myeloid cells extends the umbrella of "immunological self" and, by analogy with the thymus, may be implicated in peripheral immune tolerance.
Assuntos
Células Sanguíneas/metabolismo , Variação Genética/genética , Células Mieloides/metabolismo , Proinsulina/genética , Proinsulina/metabolismo , Splicing de RNA/genética , Autoantígenos/metabolismo , Linhagem da Célula , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patologia , Predisposição Genética para Doença , Humanos , Células Mieloides/citologia , Células Mieloides/imunologia , Proinsulina/imunologia , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Transcrição Gênica/genéticaRESUMO
A 40-year-old Korean man presented with painful swelling and tenderness of both ankle joints as well as the plantar surfaces of both feet, along with inflammatory back pain, and a purulent discharge from the urethral orifice. The patient also complained of sicca-like symptoms including dry eyes and dry mouth. An immunological analysis revealed a high titer of rheumatoid factor, positive results for antinuclear antibody and anti-Ro antibody, and a positive result for HLA-B27. An antibody titer for Chlamydia was also significantly increased. Positive results of the Schirmer's test and for keratoconjunctivitis sicca were confirmed by an ophthalmologist. These clinical manifestations were compatible with Chlamydia-induced reactive arthritis (ReA) accompanied by Sjögren's syndrome (SS). This is the first report of the combination of these two distinct disease entities in the Korean population.