RESUMO
The functional interaction of BAFF and APRIL with TNF receptor superfamily members BAFFR, TACI and BCMA is crucial for development and maintenance of humoral immunity in mice and humans. Using a candidate gene approach, we identified homozygous and heterozygous mutations in TNFRSF13B, encoding TACI, in 13 individuals with common variable immunodeficiency. Homozygosity with respect to mutations causing the amino acid substitutions S144X and C104R abrogated APRIL binding and resulted in loss of TACI function, as evidenced by impaired proliferative response to IgM-APRIL costimulation and defective class switch recombination induced by IL-10 and APRIL or BAFF. Family members heterozygous with respect to the C104R mutation and individuals with sporadic common variable immunodeficiency who were heterozygous with respect to the amino acid substitutions A181E, S194X and R202H had humoral immunodeficiency. Although signs of autoimmunity and lymphoproliferation are evident, the human phenotype differs from that of the Tnfrsf13b-/- mouse model.
Assuntos
Imunodeficiência de Variável Comum/genética , Proteínas de Membrana/genética , Mutação , Receptores do Fator de Necrose Tumoral/genética , Sequência de Aminoácidos , Formação de Anticorpos , Divisão Celular/genética , Divisão Celular/fisiologia , Feminino , Homozigoto , Humanos , Imunoglobulina M/fisiologia , Masculino , Proteínas de Membrana/química , Dados de Sequência Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/fisiologia , Linhagem , Receptores do Fator de Necrose Tumoral/química , Proteína Transmembrana Ativadora e Interagente do CAMLRESUMO
PURPOSE: Existing ways of assessing CVID patients at risk of pulmonary infections are not universally accepted. The need to identify additional prognostic factors allowed us to evaluate the anti-polysaccharide IgA and IgM responses in 125 CVID patients immunized with the 23-valent pneumococcal polysaccharide (PS) vaccine (Pneumovax(®)). METHODS: We used a new anti-PS23 IgM and IgA ELISA assay, which evaluates a global response to all 23 polysaccharides contained in Pneumovax(®). RESULTS: Anti-PS23 IgM and/or IgA antibodies were detectable in a minority of CVID patients. Antibody responses were correlated to B cell subpopulations and serum immunoglobulin concentrations. The non responders had a higher incidence of pneumonia and bronchiectasis and responders had the lowest incidence of respiratory complications. CONCLUSIONS: This new ELISA assay allows for studying vaccine response in patients on Ig replacement therapy. This test also is an additional method of evaluation of specific antibody responses representing a valuable contribution to identify prognostic marker in CVID patients.
Assuntos
Cápsulas Bacterianas/imunologia , Imunodeficiência de Variável Comum/diagnóstico , Ensaio de Imunoadsorção Enzimática , Imunoglobulina A/imunologia , Imunoglobulina M/imunologia , Infecções Pneumocócicas/diagnóstico , Vacinas Pneumocócicas/imunologia , Polissacarídeos Bacterianos/imunologia , Streptococcus pneumoniae/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Biomarcadores Farmacológicos/metabolismo , Imunodeficiência de Variável Comum/complicações , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/terapia , Feminino , Humanos , Imunoglobulinas Intravenosas/administração & dosagem , Imunoglobulinas Intravenosas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Infecções Pneumocócicas/complicações , Infecções Pneumocócicas/imunologia , Infecções Pneumocócicas/terapia , Vacinas Pneumocócicas/administração & dosagem , Prognóstico , Adulto JovemRESUMO
Autoimmune lymphoproliferative syndrome (ALPS) is mainly caused by defects in the CD95 pathway. Raised CD3+TCRαß+CD4-CD8- double negative T cells and impaired T cell apoptosis are hallmarks of the disease. In contrast, the B cell compartment has been less well studied. We found an altered distribution of B cell subsets with raised transitional B cells and reduced marginal zone B cells, switched memory B cells and plasma blasts in most of 22 analyzed ALPS patients. Moreover, 5 out of 66 ALPS patients presented with low IgG and susceptibility to infection revealing a significant overlap between ALPS and common variable immunodeficiency (CVID). In patients presenting with lymphoproliferation, cytopenia, hypogammaglobulinemia and impaired B cell differentiation, serum biomarkers were helpful in addition to apoptosis tests for the identification of ALPS patients. Our observations may indicate a role for apoptosis defects in some diseases currently classified as CVID.
Assuntos
Síndrome Linfoproliferativa Autoimune/diagnóstico , Síndrome Linfoproliferativa Autoimune/imunologia , Linfócitos B/imunologia , Imunodeficiência de Variável Comum/diagnóstico , Imunodeficiência de Variável Comum/imunologia , Proteína Ligante Fas/sangue , Interleucina-10/sangue , Vitamina B 12/sangue , Adolescente , Adulto , Agamaglobulinemia/imunologia , Apoptose , Biomarcadores/sangue , Criança , Pré-Escolar , Diagnóstico Diferencial , Proteína Ligante Fas/imunologia , Citometria de Fluxo , Humanos , Imunoglobulina G/sangue , Interleucina-10/imunologia , Pessoa de Meia-Idade , Monócitos/imunologia , Fenótipo , Linfócitos T/imunologia , Vitamina B 12/imunologia , Receptor fas/sangue , Receptor fas/imunologiaRESUMO
Dominant-negative mutations in STAT-3 have recently been found in the majority of patients with sporadic or autosomal-dominant hyper IgE syndrome (HIES). Since STAT-3 plays a role in B cell development and differentiation, we analyzed memory B cells in 20 patients with HIES, 17 of which had STAT-3 mutations. All but four patients had reduced non-switched and/or class-switched memory B cells. No reduction in these B cell populations was found in 16 atopic dermatitis patients with IgE levels above 1000 KU/L. There was no correlation between the reduction of memory B cells and the ability to produce specific antibodies. Moreover, there was no correlation between the percentage of memory B cells and the infection history. Analysis of memory B cells can be useful in distinguishing patients with suspected HIES from patients with atopic disease, but probably fails to identify patients who are at high risk of infection.
Assuntos
Linfócitos B/imunologia , Memória Imunológica/imunologia , Síndrome de Job/imunologia , Adolescente , Adulto , Anticorpos Antivirais/sangue , Formação de Anticorpos , Linfócitos B/patologia , Criança , Estudos de Coortes , DNA/química , DNA/genética , Dermatite Atópica/genética , Dermatite Atópica/imunologia , Dermatite Atópica/patologia , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Genótipo , Humanos , Imunoglobulina E/imunologia , Imunoglobulina E/metabolismo , Memória Imunológica/genética , Síndrome de Job/genética , Síndrome de Job/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Adulto JovemRESUMO
An alloreactive proliferative T-cell clone, 6065 WS, was obtained in an intrafamilial cell combination where the stimulator was a homozygous DRw11, DRw52, DQw3 son and the responder his haploidentical mother. Proliferation assays on eight local DRw11 families, 75 homozygous B-cell lines (Tenth Histocompatibility Workshop panel) and blocking assays with monoclonal antibodies showed that clone 6065 WS recognizes an epitope on the DRw11 beta 1 chain. Comparison of the reactivity of clone 6065 WS with cells expressing the three known DRw11 beta 1 amino acid sequences identified two unique amino acids at positions 71 and 86 which contribute to determining the specific recognition by the T-cell clone 6065 WS. Our data suggest that one or both of these amino acids can either be directly involved in the recognition by the T-cell receptor or responsible for critical conformation of the determinants on the DR molecule. Alternatively, they could affect recognition of a self peptide bound to the major histocompatibility complex class II molecule.
Assuntos
Epitopos/análise , Antígenos HLA-DR/imunologia , Linfócitos T/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Células Clonais , Feminino , Subtipos Sorológicos de HLA-DR , Humanos , Teste de Cultura Mista de Linfócitos , Masculino , Hibridização de Ácido NucleicoRESUMO
CD 4+ T cell lines responding specifically to Mycoplasma (M.) arthritidis were established from spleen and lymph nodes of a Lewis rat infected with M. arthritidis. The T cell response to M. arthritidis was MHC class II-restricted. M. arthritidis-reactive T cell lines also responded to syngeneic chondrocytes suggesting that M. arthritidis and chondrocytes may share a common antigenic structure. The T cell lines reacting with chondrocytes may play an important role in the chronic stage of the M. arthritidis-induced arthritis of rats by maintaining immune reactions initiated by M. arthritidis antigens and originally established to eliminate the mycoplasmas. These autoimmune reactions could perpetuate after disappearance of the mycoplasmas and possibly last for the entire lifetime.
Assuntos
Cartilagem/imunologia , Mycoplasma/imunologia , Linfócitos T/imunologia , Animais , Artrite Infecciosa/imunologia , Cartilagem/citologia , Linhagem Celular , Feminino , Técnicas In Vitro , Ativação Linfocitária , Infecções por Mycoplasma/imunologia , Fenótipo , Ratos , Ratos Endogâmicos LewRESUMO
Idiopathic CD4+ T lymphocytopenia (ICL) has been defined by the center of disease control as a rare cause of immunodeficiency with a variable clinical course and an unknown aetiology. Here we describe a 65-year old patient with relapsing generalized herpes zoster infection due to ICL and a severe panlymphocytopenia. In vitro assays revealed an enhanced activation of CD8+ T cells and an increased sensitivity of activated CD4+ T cells for cell death. The clinical outcome was substantially improved after starting the patient on a subcutaneous therapy with IL-2.
Assuntos
Herpes Zoster/tratamento farmacológico , Interleucina-2/uso terapêutico , T-Linfocitopenia Idiopática CD4-Positiva/complicações , Adulto , Idoso , Apoptose , Relação CD4-CD8 , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD8-Positivos/citologia , Candidíase/complicações , Candidíase/imunologia , Candidíase/fisiopatologia , Herpes Zoster/complicações , Herpes Zoster/imunologia , Herpes Zoster/fisiopatologia , Humanos , Interferon gama/biossíntese , Interleucina-10/biossíntese , Interleucina-2/biossíntese , Enteropatias/complicações , Enteropatias/imunologia , Enteropatias/fisiopatologia , Masculino , Pessoa de Meia-Idade , T-Linfocitopenia Idiopática CD4-Positiva/imunologia , T-Linfocitopenia Idiopática CD4-Positiva/fisiopatologia , Fator de Necrose Tumoral alfa/biossínteseRESUMO
T cell lines were established by limiting dilution of peripheral blood (PBL) and synovial fluid lymphocytes (SFL) of a patient with HLA-B27+ reactive arthritis. Among these cell lines, the CD4 phenotype was dominant. Functionally, the majority of these cell lines exhibited helper activity for the immunoglobulin production by autologous B cells and proliferated in response to autologous mononuclear cells. In most cases, this autoreactive response was associated with alloreactivity. Only one cell line, the autoreactive CD4+ T cell clone, UA-S2, which was derived from the synovial fluid, proliferated in a highly specific manner in response to a determinant associated with MHC class II products present on autologous mononuclear cells. The restriction element was shown to be associated with DR molecules by inhibition experiments with monoclonal antibodies. Within the patient's family, the capacity of mononuclear cells to stimulate a proliferative response of UA-S2 segregated together with the HLA haplotype A2 or 32, B27, Cw1, DRw11 which was contributed by the patient's mother. UA-S2 proved to be a functional helper T cell clone. In the absence of additional antigen or mitogen, it induced IgG and IgM synthesis of autologous and family members' B cells. This helper activity of UA-S2 showed the same MHC restriction as the proliferative response. Although the patient's father also typed DRw11, this haplotype was not recognized by UA-S2. It is suggested that this autoreactive T cell clone detects a microheterogeneity of the serologically defined DRw11 haplotype. Indeed, typing of the patient's family members with cellular reagents established a difference between the two DRw11 haplotypes.
Assuntos
Artrite Reumatoide/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Artrite Reumatoide/genética , Autoantígenos/imunologia , Linfócitos B/imunologia , Células Clonais/imunologia , Antígenos HLA-B/imunologia , Antígeno HLA-B27 , Antígenos HLA-DR/genética , Antígenos HLA-DR/imunologia , Subtipos Sorológicos de HLA-DR , Haplótipos , Humanos , Imunoglobulinas/biossíntese , Ativação Linfocitária , Polimorfismo GenéticoRESUMO
An autoreactive T cell clone derived from a patient with reactive arthritis, two alloreactive T cell lines, two antigen-specific T cell lines and allogeneic resting T cells were analyzed for their responses to monocytes and macrophages derived from monocytes by in vitro differentiation. The autoreactive T cell clone strongly proliferated in response to fresh monocytes and to macrophages derived from a 7 day culture, but only poorly to monocytes cultured for 2 days. In contrast, alloreactive and antigen-specific T cell lines proliferated to all stimulatory cells equally well. Finally, primary mixed lymphocyte reactions could be stimulated by both fresh and 2-day cultured monocytes, but not by in vitro derived macrophages. The impaired response of the autoreactive T cell clone to 2-day cultured monocytes could not be attributed to reduced expression of several well-defined surface molecules nor to induction of nonresponsiveness. Neither allogeneic monocytes nor cytokines (IL-1, IL-2, IL-4, IL-6) could correct the defective response of the autoreactive T cell clone. However, preculture of monocytes in the presence of interferon-gamma, IL-1, IL-4 or IL-6 retained their stimulatory capacity. Our interpretation of the selectively impaired response of the autoreactive T cell clone is that it most likely recognizes a differentiation-dependent monocyte/macrophage-specific peptide.
Assuntos
Autoantígenos/imunologia , Isoantígenos/imunologia , Ativação Linfocitária/imunologia , Monócitos/imunologia , Subpopulações de Linfócitos T/imunologia , Células Apresentadoras de Antígenos/imunologia , Antígenos de Superfície/biossíntese , Diferenciação Celular/fisiologia , Divisão Celular/imunologia , Linhagem Celular , Epitopos/imunologia , Humanos , Teste de Cultura Mista de LinfócitosRESUMO
Peripheral blood lymphocytes of 29 c-ANCA positive WG patients fulfilling the ACR classification criteria were examined for the expression of various leukocyte surface molecules by dual marker cytofluorometry (FACStar, Becton Dickinson). Activation markers such as CD25, HLA-DR, CD29 and adhesion molecules (ICAM-1 and LFA-3) were clearly elevated in this group in comparison to 40 healthy volunteers. Similar results were obtained for p-ANCA positives vasculitides (n = 13) and, unexpectedly, also for patients suffering from cholesteatoma, a chronic, bacterial infection of the middle ear (n = 21). The results are discussed in view of a pathogenic model for WG and vasculitic disorders.
Assuntos
Autoanticorpos/sangue , Moléculas de Adesão Celular/sangue , Granulomatose com Poliangiite/imunologia , Linfócitos/imunologia , Receptores de Interleucina-2/análise , Vasculite/imunologia , Adulto , Anticorpos Anticitoplasma de Neutrófilos , Antígenos CD/sangue , Antígenos CD58 , Feminino , Humanos , Imunoglobulina G/sangue , Molécula 1 de Adesão Intercelular , Masculino , Glicoproteínas de Membrana/sangue , Pessoa de Meia-IdadeRESUMO
Active vaccination of CVID patients with standard vaccines has rarely been studied in depth although some patients have been shown to develop transient vaccine-specific immunity. We addressed the question whether these patients can be identified by functional classification of their B cell subsets in vitro. Twenty-one CVID patients receiving regular IgG substitution were immunized with anti-peptide and anti-polysaccharide vaccines. Humoral vaccination responses were compared to the numbers of circulating memory B cells, CD21(low) B cells and the capacity to produce antibodies in vitro. Our findings allow four conclusions: (1) positive vaccination responses are not contradictory to the diagnosis of CVID; they occurred against polypeptide vaccines in 23% and against polysaccharide antigens in 18% of all vaccinations. (2) Class-switched antibody responses occur preferentially in patients of CVID group II. (3) A normal percentage of IgM memory B cells is necessary but not sufficient for a vaccination response to polysaccharide antigens. (4) Active vaccination in addition to IgG replacement therapy should be performed in patients of CVID type II - especially in case of vaccines for which passive protection cannot be guaranteed.
Assuntos
Linfócitos B/imunologia , Imunodeficiência de Variável Comum/imunologia , Peptídeos/uso terapêutico , Polissacarídeos/uso terapêutico , Vacinação , Adulto , Idoso , Formação de Anticorpos/imunologia , Linfócitos B/classificação , Imunodeficiência de Variável Comum/classificação , Imunodeficiência de Variável Comum/terapia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Memória Imunológica , Subpopulações de Linfócitos/classificação , Subpopulações de Linfócitos/imunologia , Masculino , Pessoa de Meia-Idade , Vacinas Pneumocócicas/uso terapêutico , Streptococcus pneumoniae/imunologiaRESUMO
The normal metabolism of mitochondria in T lymphocytes is unknown, as are the effects from nucleoside-analogue reverse-transcriptase inhibitors that impair mitochondrial polymerase- gamma . We isolated peripheral-blood CD4 and CD8 T lymphocytes from 6 healthy men and stimulated them with anti-CD3 and anti-CD28 antibodies, in the presence and in the absence of didanosine (ddI). In the absence of ddI, mitosis of T lymphocytes was paralleled by a transient up-regulation of both mtDNA and production of lactate. In CD4 lymphocytes, 10-day incubation with ddI at concentrations of 11.8 mu mol/L, 35.4 mu mol/L, 59.0 mu mol/L, and 118.0 mu mol/L induced (1) a concentration-dependent reduction of both mtDNA (to 73%, 29%, 24%, and 23%, respectively, of the levels in control samples) and subunit II of mtDNA-encoded cytochrome c oxidase (to 86%, 81%, 55%, and 31%, respectively, of the levels in control samples) and (2) a concentration-dependent increase in production of lactate (to 139%, 222%, 276%, and 312%, respectively, of the levels in control samples). Activation of lymphocytes (which was measured in terms of expression of CD25) was unaffected. Mitochondrial depolarization (assessed by staining with JC-1) was observed as early as day 7 of incubation. All changes were time dependent and also were observed in isolated CD8 lymphocytes. Electron microscopy revealed enlarged mitochondria with vacuoles, inclusions, and reduced electron density. ddI at a concentration of 11.8 mu mol/L induced changes that bordered statistical significance. After stimulation, there was a wide range in the change of mtDNA content in lymphocytes. Therefore, mtDNA measurements in blood are not necessarily a marker for the mitochondrial toxicity of ddI. Nevertheless, ddI does lead to depletion of mtDNA in lymphocytes and to functional impairment.
Assuntos
Fármacos Anti-HIV/efeitos adversos , DNA Mitocondrial/efeitos dos fármacos , DNA Mitocondrial/metabolismo , Didanosina/efeitos adversos , Inibidores da Transcriptase Reversa/efeitos adversos , Linfócitos T/efeitos dos fármacos , Adulto , Fármacos Anti-HIV/administração & dosagem , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Didanosina/administração & dosagem , Humanos , Ativação Linfocitária , Masculino , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Doenças Mitocondriais/induzido quimicamente , Inibidores da Transcriptase Reversa/administração & dosagem , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
Recent reports have described reduced populations of CD27+ memory B cells and increased percentages of undifferentiated B cells in peripheral blood of patients with common variable immunodeficiency (CVID). This work has prompted two attempts to classify CVID based on rapid flow cytometric quantification of peripheral blood memory B cells and immature B cells. Evidence to support the hypothesis that such in vitro B cell classification systems correlate with clinical subtypes of CVID is being sought. For the classification to be useful in routine diagnosis, it is important that the flow cytometric method can be used without prior separation of peripheral blood mononuclear cells (PBMC). We have examined 23 CVID patients and 24 controls, using both PBMC and whole blood, and find an excellent correlation between these methods. The reproducibility of the method was excellent. We classified the CVID patients by all three of the existing classifications, including secretion of immunoglobulin by B cells in vitro as described by Bryant, as well as the more recent flow cytometric classification methods. Only one patient changed classification as a result of using whole blood.
Assuntos
Linfócitos B/imunologia , Imunodeficiência de Variável Comum/imunologia , Adolescente , Adulto , Idoso , Imunodeficiência de Variável Comum/classificação , Feminino , Citometria de Fluxo/métodos , Humanos , Memória Imunológica/imunologia , Leucócitos Mononucleares/imunologia , Contagem de Linfócitos/métodos , Masculino , Pessoa de Meia-Idade , Receptores de Complemento 3d/imunologia , Reprodutibilidade dos Testes , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
The soluble, NAD+-reducing hydrogenase in intact cells of Alcaligenes eutrophus was inactivated by oxygen when electron donors such as hydrogen or pyruvate were available. The sole presence of either oxygen or oxidizable substrates did not lead to inactivation of the enzyme. Inactivation occurred similarly under autotrophic growth conditions with hydrogen, oxygen and carbon dioxide. The inactivation followed first order reaction kinetics, and the half-life of the enzyme in cells exposed to a gas atmosphere of hydrogen and oxygen (8:2, v/v) at 30 degrees C was 1.5h. The process of inactivation did not require ATP-synthesis. There was no experimental evidence that the inactivation is a reversible process catalyzed by a regulatory protein. The possibility is discussed that the inactivation is due to superoxide radical anions (O2-) produced by the hydrogenase itself.
Assuntos
Alcaligenes/enzimologia , Oxirredutases/antagonistas & inibidores , Trifosfato de Adenosina/farmacologia , Azidas/farmacologia , Dióxido de Carbono/farmacologia , Cianetos/farmacologia , Dinitrofenóis/farmacologia , Hidrogenase , Oxigênio/farmacologia , Azida SódicaRESUMO
Neutrophils are the target of autoantibodies in Wegener's granulomatosis (WG). In this study, granulocyte function and surface marker expression were investigated in patients with WG. The oxidative burst in response to phorbol myristate acetate (PMA) was tested with granulocytes of 25 patients with histologically proven WG. A significantly diminished percentage of oxygen radical-producing cells was found in patients with active disease. Surface antigen expression of CD11b and LAM-1 was analysed on granulocytes of 20 patients with WG. Whereas the expression of CD11b was normal, surface expression of LAM-1 was decreased in nine cases with WG. The decrease of LAM-1 correlated with disease activity. Phagocytosis of Escherichia coli was tested in 10 patients with WG, and normal values were found in all cases. We conclude that down-regulation of LAM-1 may be a marker of disease activity in WG. The altered response to PMA may indicate functional changes in granulocyte reactivity due to autoantibody-induced damage of the granulocyte membrane.
Assuntos
Moléculas de Adesão Celular/metabolismo , Granulomatose com Poliangiite/fisiopatologia , Neutrófilos/fisiologia , Regulação para Baixo , Feminino , Humanos , Selectina L , Masculino , Fagocitose , Explosão RespiratóriaRESUMO
Four type II collagen-specific T cell lines established from the peripheral blood of a healthy donor were studied in detail. These CD4+ T cell lines with an alpha/beta T cell receptor proliferated in response to native and denatured human and chicken type II collagen and human type I collagen, but not to human type IV collagen or other potentially arthritogenic antigens. The T cell response showed typical dose response characteristics, peaked between 30 and 48 h, was major histocompatibility complex class II restricted and not due to a mitogenic effect. Type II collagen-reactive T cells could hardly be detected in freshly isolated peripheral blood mononuclear cells from healthy donors, as revealed by limiting dilution analysis (frequency less than 1/100,000). By prestimulation in bulk cultures for 10 days, type II collagen-reactive T cells could be approximately 1000-fold enriched. However, in these limiting dilution cultures, collagen-reactive T cells could only be observed in a narrow window of cell concentrations, suggesting that type II collagen-reactive T cells may be controlled by suppressive mechanisms in healthy persons.
Assuntos
Colágeno/imunologia , Linfócitos T/imunologia , Adulto , Células Apresentadoras de Antígenos/imunologia , Linhagem Celular , Humanos , MasculinoRESUMO
Using a limiting dilution system, frequencies of Borrelia burgdorferi-reactive T cells were determined in the blood and synovial fluid of four patients with chronic Lyme arthritis (LA), one patient with acrodermatitis chronica atrophicans (ACA), two patients with other inflammatory joint diseases, and two healthy individuals. B. burgdorferi-reactive precursor T cells ranged from 1/750 to 1/8220 in case of LA and ACA patients and from 1/820 to 1/31 400 in case of controls. In vivo activated B. burgdorferi-reactive T cells were almost absent in control subjects. With one exception, they were detected in LA patients at frequencies ranging from 1/1 300 to 1/15 400. Interestingly, even after successful antibiotic therapy of LA patients, similar frequencies of in vivo activated B. burgdorferi-reactive T cells were observed in the peripheral blood, provided that low cell concentrations were used for culture. At higher cell numbers, the fraction of B. burgdorferi-reactive T cells apparently dropped, suggesting regulatory phenomena.
Assuntos
Artrite Infecciosa/imunologia , Grupo Borrelia Burgdorferi/imunologia , Doença de Lyme/imunologia , Linfócitos T/imunologia , Adulto , Antibacterianos/uso terapêutico , Contagem de Células , Feminino , Humanos , Memória Imunológica , Doença de Lyme/tratamento farmacológico , Ativação Linfocitária/imunologia , Masculino , Pessoa de Meia-Idade , Líquido Sinovial/imunologiaRESUMO
Peripheral blood (PBL) and synovial fluid lymphocytes (SFL) from 18 patients with definite rheumatoid arthritis (RA) and from one patient with Reiter's disease (RD) were examined for their capacity to absorb quantitatively interleukin-2 (IL-2) from a standardized, lectin-free IL-2 source. For comparison normal ConA blasts and PBL from various inflammatory and noninflammatory diseases as well as from healthy control persons were studied. IL-2 activity was quantitated by measuring 3H-thymidine-2-deoxyriboside uptake in the IL-2 dependent murine T cell line CTL6. ConA blasts exhibited a high IL-2 absorption capacity and served as a positive control for calibrating the absorption assay. In a population of normal PBL at least 5-10% of ConA blasts were required to detect IL-2 absorption. Significant absorption was assumed if more than 50% of IL-2 activity was removed from 200 microliters of a lectin-free IL-2 standard following incubation with 5 X 10(6) lymphoid cells for 2 h at 4 degrees C; this criterion was fulfilled with 8 out of 20 SFL and 4 out of 14 PBL preparations from RA patients. As a rule SFL absorbed more IL-2 than PBL. Control PBL did not absorb significant quantities of IL-2. PBL from the RD patient apparently produced an IL-2 inhibitor during incubation with the IL-2 standard. IL-2 absorption by ConA blasts and SFL was fully inhibited by preincubation of the absorbing cells with monoclonal anti-TAC antibody, a reagent known to react with the human IL-2 receptor. The results are discussed in view of current concepts of antigen/mitogen induced T cell activation.
Assuntos
Artrite Reumatoide/imunologia , Interleucina-2/imunologia , Líquido Sinovial/imunologia , Linfócitos T/imunologia , Adulto , Idoso , Anticorpos Monoclonais/imunologia , Células Cultivadas , Concanavalina A/farmacologia , Feminino , Humanos , Interleucina-2/análise , Masculino , Pessoa de Meia-Idade , Receptores Imunológicos/análise , Receptores Imunológicos/imunologia , Receptores de Interleucina-2 , Líquido Sinovial/citologiaRESUMO
A novel proteinase, termed human T cell-associated serine proteinase (HuTSP), has been highly purified from a human CD8+ T lymphocyte clone. By using a panel of chromogenic model peptide substrates the enzyme was found to specifically recognize L-arginine and to cleave Tos-Gly-Pro-Arg-nitroanilide with high efficiency at a pH optimum of 10.5-11. Exposure to class-specific proteinase inhibitors revealed that HuTSP is a serine endopeptidase. The enzyme has a mol. mass of approximately 50 kDa (non-reduced) and of approximately 25-30 kDa (reduced) when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggesting HuTSP to be a disulfide-linked dimer. The enzyme is shown to be inducible by lectin in both CD4+ and CD8+ lymphocytes. Moreover, HuTSP was detected in a number of independent CD4+ and CD8+ T cell clones and was found to be released from effector cells upon ligand binding to the CD3-T cell receptor complex.
Assuntos
Serina Endopeptidases/isolamento & purificação , Linfócitos T Citotóxicos/enzimologia , Linfócitos T Auxiliares-Indutores/enzimologia , Células Clonais/enzimologia , Indução Enzimática , Granzimas , Humanos , Ativação Linfocitária , Serina Endopeptidases/biossíntese , Serina Endopeptidases/metabolismo , Especificidade por Substrato , Linfócitos T Citotóxicos/metabolismo , Linfócitos T Auxiliares-Indutores/metabolismoRESUMO
Several lines of evidence argue in favour of an involvement of T cells in the pathogenesis of Wegener's granulomatosis (WG). These include the presence of highly specific IgG autoantibodies to proteinase 3, perivascular T-cell infiltrates and elevated amounts of soluble interleukin-2 (IL-2) receptors in patient's serum. In order to further address this question we evaluated by double immunofluorescence and flow cytometry the expression of several cell surface molecules associated with T-cell activation. As compared to healthy controls (n = 15), the CD4+ subset was significantly diminished, while the percentage of CD8+ T cells was elevated in WG patients (n = 24). Within the CD4+ T-cell subset we found a highly significant increase in activation/memory markers (CD25, CD29, HLA-DR). Within the CD8+ T-cell subset the expression of CD11b, CD29 and CD57 was significantly elevated, while the expression of VD28 was reduced. The use of 10 V beta-, 1 V alpha- and 1 V gamma-specific monoclonal reagents failed to reveal any significant bias in the peripheral T-cell receptor V-gene repertoire of WG patients. There was also no correlation between T-cell activation markers and laboratory parameters [C-reactive protein (CRP), ESR], disease duration or therapy. A significant correlation was found only for the degree of organ involvement and the increase in CD4+ T cells coexpressing HLA-DR, as well as the increase in CD57 expression on CD8+ T cells. In conclusion, both CD4+ and CD8+ T-cell subsets were activated in WG. Cytotoxic CD8+CD57+CD11b+CD28- T cells may directly contribute to damage of vascular endothelium.