RESUMO
Cerebral palsy (CP) is an early onset, non-progressive, neuromotor disorder. Adolescence is the transition from childhood to adulthood when changes in physical and emotional aspects and self-perception occur further imposing an impact to quality of life (QoL) in individuals with CP. Cerebral Palsy Quality of Life (CP QoL) Teen is a questionnaire examining different domains of QoL for adolescents with CP. This study is aimed at translating and validating self-report and proxy-report CP QoL-Teen (HK). Prior approval of translation has been obtained. Forward and backward translations were performed following standardized translation procedures. Participants and their caregivers were asked to complete self-report and proxy-report CP QoL-Teen (HK), and Child Health Questionnaire (CHQ). Internal consistency and test-retest reliability were assessed by Cronbach's alpha and intraclass correlation coefficient (ICC), respectively. Concurrent validity was evaluated by Spearman's rank correlation between subscales of CP QoL-Teen (HK) and CHQ as well as expanded and revised version of Gross Motor Function Classification System (GMFCS-E&R). Ninety-six participants completed the study. Of these, twenty participants completed CP QoL-Teen (HK) twice. Cronbach's α of CP QoL-Teen (HK) ranged from 0.84 to 0.95 suggesting excellent internal consistency. Moderate to excellent test-retest reliability were demonstrated in all subscales of CP QoL-Teen (HK) (self-report: ICC = 0.46-0.8; proxy-report: ICC = 0.40-0.72, p < 0.05). Weak to moderate association between subscales of CP QoL-Teen (HK) and CHQ (self-report: rs = 0.24-0.61; proxy-report: rs = - 0.41-0.60) was reported. CONCLUSION: This study showed that CP QoL-Teen (HK) has good psychometric properties. It is a valid and reliable tool to assess quality of life of adolescents with CP. WHAT IS KNOWN: ⢠Cerebral Palsy Quality of life-Teen (CP QoL-Teen) is a validated tool with strong psychometric properties and clinical utility in gauging the QoL in adolescents with CP during their transition from childhood to adulthood when changes in physical and emotional aspects and self-perception occur. Yet, a locally validated tool is lacking in measuring the QoL for adolescents with CP in Hong Kong. WHAT IS NEW: ⢠The Chinese translated version CP QoL-Teen (HK) is a valid and reliable tool to assess quality of life of adolescents with CP tailoring to the local cultural and social background with good psychometric properties being demonstrated.
Assuntos
Paralisia Cerebral , Qualidade de Vida , Inquéritos e Questionários , Adolescente , Criança , Humanos , Adulto Jovem , População do Leste Asiático , Hong Kong , Psicometria/métodos , Qualidade de Vida/psicologia , Reprodutibilidade dos Testes , TraduçõesRESUMO
BACKGROUND: The purpose of this study was to examine the adoption trends of emergency laparoscopic colorectal surgery in the province of Ontario. STUDY DESIGN: We conducted a retrospective time-series analysis examining rates of emergency colorectal surgery among 10.5 million adults in Ontario, Canada from April 1, 2002 to December 31, 2009. We linked administrative claims databases and the Ontario Cancer Registry to assess procedure rates over time. Procedure trends were assessed using time-series analysis. RESULTS: Over the 8-year period, 29,676 emergency colorectal procedures were identified. A total of 2582 (8.7%) were performed laparoscopically and 27,094 (91.3%) were open. Open and laparoscopic patients were similar with respect age, sex, and Charlson Comorbidity Index. The proportion of surgery for benign (63.8% of open cases vs. 65.6% laparoscopic, standardized difference=0.04) and malignant disease (36.2% open vs. 34.4% laparoscopic, standardized difference=0.04) was equal between groups. The percentage of emergency colorectal surgery performed laparoscopically increased from 5.7% in 2002 to 12.0% in 2009 (P<0.01). The use of laparoscopy increased for both benign and malignant disease. Statistically significant upward trends in laparoscopic surgery were seen for inflammatory bowel disease (P<0.01), obstruction (P<0.01), and colon cancer (P<0.01). From 2002 to 2009, annual procedure rates increased at a greater rate in nonacademic centers (P<0.01). CONCLUSIONS: Laparoscopic emergency colorectal surgery has increased significantly between 2002 and 2009 for both benign and malignant disease and for a wide range of diagnoses. This was driven in part by steadily rising usage of laparoscopy in nonacademic centers.
Assuntos
Neoplasias Colorretais/cirurgia , Cirurgia Colorretal/tendências , Emergências/epidemiologia , Laparoscopia/tendências , Vigilância da População/métodos , Idoso , Neoplasias Colorretais/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Ontário/epidemiologia , Estudos Retrospectivos , Fatores de TempoRESUMO
The lung is the portal of entry for Mycobacterium tuberculosis (Mtb) and animal experimental evidence indicates that local immune defense mechanisms are crucial for protective immunity. Immunization via the lower respiratory tract efficiently induces a dividing, activated, antigen-dependent, lung-resident, memory T-cell population, which is partly recoverable by bronchoalveolar lavage. These cells can inhibit the growth of Mtb in the lungs immediately after infection. Delivery of appropriate signals to the lung innate immune system is critical for induction of effective local immunity. In contrast after parenteral immunization, antigen-specific cells may be found in lung tissue but few are recoverable by lavage and inhibition of mycobacterial growth is delayed. Harnessing both local and systemic immunity can provide highly effective protection in animal models and the evidence suggests that taken in aggregate, multiple animal models may predict the success of novel vaccine strategies in humans.
Assuntos
Mycobacterium tuberculosis/imunologia , Vacinas contra a Tuberculose/imunologia , Tuberculose/imunologia , Tuberculose/prevenção & controle , Animais , Vacina BCG/imunologia , Humanos , Imunidade InataRESUMO
This study aimed to (1) compare the postural control strategies, sensory organization of balance control, and lower limb muscle performance of children with and without developmental coordination disorder (DCD) and (2) determine the association between postural control strategies, sensory organization parameters and knee muscle performance indices among children with DCD. Fifty-eight DCD-affected children and 46 typically developing children participated in the study. Postural control strategies and sensory organization were evaluated with the sensory organization test (SOT). Knee muscle strength and time to produce maximum muscle torque (at 180°/s) were assessed using an isokinetic machine. Analysis of variance was used to compare the outcome variables between groups, and multiple regression analysis was used to examine the relationships between postural control strategies, sensory organization parameters, and isokinetic indices in children with DCD. The DCD group had significantly lower strategy scores (SOT conditions 5 and 6), lower visual and vestibular ratios, and took a longer time to reach peak torque in the knee flexor muscles than the control group (p>0.05). After accounting for age, sex, and body mass index, the vestibular ratio explained 35.8% of the variance in the strategy score of SOT condition 5 (p<0.05). Moreover, the visual ratio, vestibular ratio, and time to peak torque of the knee flexors were all significant predictors (p<0.05) of the strategy score during SOT condition 6, accounting for 14, 19.7, and 19.8% of its variance, respectively. The children with DCD demonstrated deficits in postural control strategy, sensory organization and prolonged duration of muscle force development. Slowed knee muscle force production combined with poor visual and vestibular functioning may result in greater use of hip strategy by children with DCD in sensory challenging environments.
Assuntos
Transtornos das Habilidades Motoras/fisiopatologia , Força Muscular/fisiologia , Postura/fisiologia , Transtornos de Sensação/fisiopatologia , Estudos de Casos e Controles , Criança , Estudos Transversais , Feminino , Articulação do Quadril/fisiologia , Humanos , Articulação do Joelho/fisiologia , Masculino , Destreza Motora/fisiologia , Contração Muscular/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Vestíbulo do Labirinto/fisiologiaRESUMO
Immunological memory consists of expanded clones of T and B lymphocytes that show an increased rate of cell division and shortened telomeres compared with naïve cells. However, exhaustion of clones is delayed by kinetic heterogeneity within clones and altered survival and up-regulation of telomerase. Prolonged maintenance of protective B-cell immunity is T-cell dependent and requires a balance between plasma cells and memory B cells. Protective T-cell immunity also requires correct quality of T cells and that they are located appropriately.
Assuntos
Linfócitos B/imunologia , Memória Imunológica/imunologia , Linfócitos T/imunologia , Humanos , Ativação Linfocitária/imunologia , Telomerase/imunologiaRESUMO
CD45 is a haemopoietic tyrosine phosphatase, crucial for lymphocyte signalling. Two polymorphisms (C77G and A138G), which alter CD45 isoform expression, are associated with autoimmune and infectious diseases. Using HapMap data, we show that there is substantial linkage disequilibrium across the CD45 gene (PTPRC), with similar patterns in different populations. Employing a set of single nucleotide polymorphisms, correlated with a substantial proportion of variation across this gene, we tested for association with type 1 diabetes, Graves' disease in a Japanese population, hepatitis C in UK population and tuberculin response in a Chinese population. A limited number of common haplotypes was found. Most 138G alleles are present on only one haplotype, which is associated with Graves' disease, supporting previous data that A138G is a functionally important CD45 polymorphism.
Assuntos
Diabetes Mellitus Tipo 1/genética , Predisposição Genética para Doença , Doença de Graves/genética , Antígenos Comuns de Leucócito/genética , Polimorfismo de Nucleotídeo Único , Alelos , Ascaríase/genética , Ascaríase/parasitologia , China , Haplótipos , Hepatite C/genética , Humanos , Japão , Contagem de Ovos de Parasitas , Tuberculina/imunologia , Reino UnidoRESUMO
CD45, the leucocyte common antigen, is a haematopoietic cell specific tyrosine phosphatase. Human polymorphic CD45 variants are associated with autoimmune and infectious diseases and alter the phenotype and function of lymphocytes, establishing CD45 as an important regulator of immune function. Here we report four patients with diverse diseases with unusual clinical features. All four have the C77G polymorphism of CD45 exon 4, which alters the splicing and CD45RA/CD45R0 phenotype of lymphocytes. We suggest that C77G may be a contributing factor in these unusual cases.
Assuntos
Imunodeficiência de Variável Comum/genética , Antígenos Comuns de Leucócito/genética , Infecções Oportunistas/genética , Polimorfismo Genético , Abscesso/genética , Abscesso/imunologia , Adulto , Criança , Imunodeficiência de Variável Comum/imunologia , Feminino , Predisposição Genética para Doença , Humanos , Hospedeiro Imunocomprometido/genética , Masculino , Pessoa de Meia-Idade , Miocardite/genética , Miocardite/imunologia , Infecções Oportunistas/imunologia , Splicing de RNA , Infecções por Salmonella/genética , Infecções por Salmonella/imunologia , Esplenopatias/genética , Esplenopatias/imunologiaRESUMO
BACKGROUND: A polymorphism in exon 4 (C77G) of CD45 that alters CD45 splicing has been associated with autoimmune and infectious diseases in humans. OBJECTIVE: To investigate the effect of C77G in hepatitis C virus (HCV) infected individuals and study the phenotype and function of peripheral blood mononuclear cells (PBMC) from healthy and hepatitis C infected C77G carriers. RESULTS: C77G individuals showed an increased proportion of primed CD45RA and effector memory CD8 T cells and more rapid activation of the lymphocyte specific protein tyrosine kinase (Lck) following CD3 stimulation. Transgenic mice with CD45 expression mimicking that in human C77G variants had more activated/memory T cells, more rapid proliferative responses, and activation of Lck. CONCLUSIONS: Changes in CD45 isoform expression can alter immune function in human C77G variants and CD45 transgenic mice. The C77G allele may influence the outcome of HCV infection.
Assuntos
Portador Sadio/imunologia , Hepatite C/genética , Hepatite C/imunologia , Antígenos Comuns de Leucócito/genética , Antígenos Comuns de Leucócito/metabolismo , Animais , Biomarcadores , Proliferação de Células , Éxons/genética , Feminino , Citometria de Fluxo , Expressão Gênica , Humanos , Ativação Linfocitária/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Transdução de Sinais , Linfócitos T/citologia , Linfócitos T/imunologiaRESUMO
The center for circadian rhythms in mammals is the suprachiasmatic nucleus (SCN) of the hypothalamus, composed of single cell circadian oscillators driven by a transcriptional/translational feedback loop where clock proteins drive clock gene expression. These genes are expressed in peripheral tissues and several brain areas outside the SCN. It is likely that some peripheral oscillators are synchronized by the SCN. The pineal hormone melatonin plays an important role in the entrainment of circadian rhythms through feedback to the SCN. Melatonin also plays a role in reproduction, including direct effects on GnRH-secreting GT1-7 neurons. The intrinsic rhythmicity of GnRH neurons suggests that these neurons may express the components of the circadian oscillator. Using the GT1-7 cell line, we demonstrate expression of the circadian rhythm genes, clock, BMAL1,timeless (tim), period1,period2, cryptochrome1, andcryptochrome2. Furthermore, semiquantitative RT-PCR demonstrates that BMAL1, period1, andperiod2 as well as GnRH mRNAs are expressed with a circadian-like rhythm after synchronization over 54 h. With available antibodies, we demonstrated CLOCK, BMAL1, and PERIOD1 protein expression in these cells, with BMAL1 protein levels showing a rhythmic expression pattern. In addition, receptors for melatonin, mt1 and MT2, also show a circadian expression pattern in the GT1-7 cells, and their expression is down-regulated by melatonin treatment. These findings suggest that the components of the clock machinery in mammals may play a role in GnRH neuronal function.
Assuntos
Ritmo Circadiano/fisiologia , Hormônio Liberador de Gonadotropina/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Neurônios/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Fatores de Transcrição ARNTL , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Proteínas CLOCK , Proteínas de Ciclo Celular , Expressão Gênica/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Sistema Hipotálamo-Hipofisário/citologia , Neurônios/metabolismo , Proteínas Nucleares/genética , Proteínas Circadianas Period , Sistema Hipófise-Suprarrenal/citologia , Receptor MT1 de Melatonina/genética , Receptor MT2 de Melatonina/genética , Transativadores/genética , Fatores de Transcrição/genéticaRESUMO
The photodegradation kinetics of atrazine (2-chloro-6-(ethylamino)-4-isopropylamino-1,3,5-triazine) and ametryne (2-methylthio-4-ethylamino-6-isopropylamino-s-triazine), in fresh and coastal salt water from Barbados, were measured under irradiation with artificial solar and UV254-radiation. The first-order rate constants were greater for ametryne than for atrazine, and the rates were reduced in seawater relative to fresh water, and in soil slurries relative to fresh water. However, rates were accelerated in the presence of iron(III) at pH 3 due to photo-Fenton type processes. This rate enhancement was reduced at ambient pH values (pH 7-7.5) representative of surface water in Barbados. These results have important implications for the relative persistence of these contaminants in aquatic environments in tropical areas.
Assuntos
Atrazina/química , Herbicidas/química , Fotólise , Poluentes do Solo/metabolismo , Triazinas , Poluentes Químicos da Água/metabolismo , Atrazina/efeitos da radiação , Barbados , Biodegradação Ambiental , Catálise , Água Doce/química , Herbicidas/efeitos da radiação , Concentração de Íons de Hidrogênio , Água do Mar/química , Raios Ultravioleta , Poluentes Químicos da Água/efeitos da radiaçãoRESUMO
An ideal vaccine is relatively easy to define, but few real vaccines approach the ideal and no vaccines exist for many organisms, for which a vaccine is the only realistic protective strategy in the foreseeable future. Many difficulties account for the failure to produce these vaccines. All micro-organisms deploy evasion mechanisms that interfere with effective immune responses and, for many organisms, it is not clear which immune responses provide effective protection. However, recent advances in methods for studying immune response to pathogens have provided a better understanding of immune mechanisms, including immunological memory, and led to the realisation that the initiation of immune responses is a key event requiring triggering through 'danger' signals. Based on these findings, the development of novel adjuvants, vectors and vaccine formulations allowing stimulation of optimal and prolonged protective immunity should lead to the introduction of vaccines for previously resistant organisms.
Assuntos
Imunidade Celular , Memória Imunológica , Vacinas/imunologia , Humanos , Subpopulações de Linfócitos T/imunologia , VacinaçãoRESUMO
Management of an effective national vaccine strategy necessitates careful planning. In the face of budgetary constraints and the likely development of many new vaccines over the next few years, a rational choice of which vaccines to use and how best to use them will depend on first class disease surveillance, economic analysis of cost effectiveness and mathematical modelling to ensure optimal vaccine delivery. Effective immunisation programmes require strategic planning that integrates the outputs of these parameters with available health facilities with the least possible disruption. At the present time, the greatest threat to vaccination is resistance to continuing vaccination in the face of declining prevalence of many infectious diseases and heightened fears over vaccine safety. Re-assurance of the public that vaccines are safe demands effective detection of vaccine-related side-effects and rigorous investigation of any safety concerns.
Assuntos
Política de Saúde , Programas de Imunização , Planejamento em Saúde , Humanos , Modelos Imunológicos , Reino Unido , Vacinas/efeitos adversosRESUMO
Many cytotoxic CD8+ T cell responses are dependent on the interactions between CD40 ligand on the helper CD4+ T cell and CD40 on the APC. Although CD40 triggering of dendritic cells (DC) has been shown to mature the DC by increasing the level of expression of costimulatory molecules and inducing IL-12 secretion, the precise mechanisms by which CD40-CD40 ligand interactions allow DC to drive CTL responses remain unknown. We have used an in vitro model in which naive polyclonal CD8+ T cells can be activated by bone marrow-derived DC to investigate factor(s) that are responsible for this CD40-dependent generation of CTLs. DC modulated with agonistic anti-CD40 mAb (aCD40) are able to generate Ag-specific CTL responses while DC modulated with the microbial stimulus LPS alone do not. We compared the Ag-presenting capacity, levels of costimulatory molecules, and release of cytokines and chemokines of DC modulated with aCD40 to that of DC modulated by LPS. None of the factors assayed account for the unique capacity of anti-CD40-matured DC to drive CTL but this model provides a simplified system for further investigation. Although we attempted to use an LPS-free system for these studies, we are unable to rule out the possibility that very low levels of endotoxin (<20 pg/ml) may synergize with CD40 ligation in the generation of CTLs.
Assuntos
Adjuvantes Imunológicos/farmacologia , Antígenos CD40/fisiologia , Ligante de CD40/fisiologia , Células Dendríticas/imunologia , Lipopolissacarídeos/farmacologia , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Citotóxicos/imunologia , Animais , Apresentação de Antígeno , Antígenos CD40/imunologia , Antígenos CD40/metabolismo , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Células Cultivadas , Células Clonais/imunologia , Citocinas/biossíntese , Citotoxicidade Imunológica/imunologia , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Relação Dose-Resposta Imunológica , Proteínas do Ovo/imunologia , Proteínas do Ovo/metabolismo , Feminino , Antígenos de Histocompatibilidade Classe II/biossíntese , Soros Imunes/farmacologia , Interfase/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ovalbumina/imunologia , Ovalbumina/metabolismo , Ovalbumina/farmacologia , Fragmentos de Peptídeos , Células Tumorais Cultivadas , Regulação para Cima/imunologiaRESUMO
The CD45 antigen is essential for normal antigen receptor-mediated signalling in lymphocytes, and different patterns of splicing of CD45 are associated with distinct functions in lymphocytes. Here we show that abnormal CD45 splicing caused by a C77G transversion in exon A of the gene encoding CD45 (PTPRC) is associated with increased susceptibility to HIV-1 infection.
Assuntos
Predisposição Genética para Doença , Infecções por HIV/genética , HIV-1 , Antígenos Comuns de Leucócito/genética , Mutação Puntual , Processamento Alternativo , Éxons/genética , Infecções por HIV/imunologia , Humanos , Antígenos Comuns de Leucócito/metabolismo , Leucócitos Mononucleares/imunologiaRESUMO
A 77G allele of the gene encoding CD45, also known as the protein tyrosine phosphatase receptor-type C gene (PTPRC), has been associated with multiple sclerosis (MS). Here we determine allele frequencies in large numbers of MS patients, primary immunodeficiencies linked to major histocompatibility complex (MHC) locus and over 1,000 controls to assess whether aberrant splicing of PTPRC caused by the 77C-->G polymorphism results in increased susceptibility to these diseases. Our results show no difference in the frequency of the 77G allele in patients and controls and thus do not support a causative role for the polymorphism in the development of disorders with a strong autoimmune component in etiology.
Assuntos
Doenças Autoimunes/genética , Antígenos Comuns de Leucócito/genética , Complexo Principal de Histocompatibilidade/genética , Mutação Puntual , Animais , Cromossomos Humanos Par 1 , Genótipo , Humanos , Splicing de RNARESUMO
The leukocyte common (CD45) Ag is essential for normal T lymphocyte function and alternative splicing at the N terminus of the gene is associated with changes in T cell maturation and differentiation. Recently, a statistically significant association was reported in a large series of human thymus samples between phenotypically abnormal CD45 splicing and the presence of the CC chemokine receptor 5 deletion 32 (CCR5del32) allele, which confers resistance to HIV infection in homozygotes. We show here that abnormal splicing in these thymus samples is associated with the presence of the only established cause of CD45 abnormal splicing, a C77G transversion in exon A. In addition we have examined 227 DNA samples from peripheral blood of healthy donors and find no association between the exon A (C77G) and CCR5del32 mutations. Among 135 PBMC samples, tested by flow cytometric analysis, all those exhibiting abnormal splicing of CD45 also showed the exon A C77G transversion. We conclude that the exon A (C77G) mutation is a common cause of abnormal CD45 splicing and that further disease association studies of this mutation are warranted.
Assuntos
Processamento Alternativo/imunologia , Éxons/genética , Éxons/imunologia , Antígenos Comuns de Leucócito/genética , Mutação Puntual , Processamento Alternativo/genética , Criança , Citosina , Citometria de Fluxo , Ligação Genética/imunologia , Guanina , Humanos , Antígenos Comuns de Leucócito/sangue , Leucócitos Mononucleares/enzimologia , Leucócitos Mononucleares/imunologia , Proteínas Tirosina Fosfatases/sangue , Proteínas Tirosina Fosfatases/genética , Receptores CCR5/sangue , Receptores CCR5/genética , Deleção de Sequência/imunologia , Timo/enzimologia , Timo/imunologiaRESUMO
Heteroduplex analysis allows global analysis of T cell receptor clonality. This review outlines the method, compares it to other available techniques for the study of clonality and reviews current literature on how these are being used to investigate alterations in the T cell repertoire within elderly individuals.
Assuntos
Envelhecimento/imunologia , Genes Codificadores dos Receptores de Linfócitos T , Ácidos Nucleicos Heteroduplexes/genética , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/imunologia , Idoso , Animais , DNA/genética , HumanosRESUMO
Expression of the leucocyte common antigen (CD45) in mammals is restricted to the nucleated lineages of haematopoietic cells. It appears in early progenitors in the bone marrow and is expressed at the surface of these cells throughout their differentiation. However, at least in T cells, the pattern of expression switches between different isoforms during the successive stages of differentiation in the thymus and after activation in the periphery. In order to understand the mechanisms controlling the transcription of the human CD45 gene, 2.7 kbp of the 5'-flanking region were sequenced and analysed for their ability to direct expression of a reporter gene. The only region with promoter activity was localized within the first intron of the gene. This promoter shows no tissue specificity but could be enhanced by a heterologous enhancer. Mobility shift assays showed complex but specific protein binding. The sequence in this region lacks similarity with known promoters or initiators but is highly conserved in evolution. No transcription initiation could be detected within or downstream of this region, suggesting that this might be a new type of RNA polymerase II promoter able to drive transcription from an upstream sequence. An additional exon was also found upstream of exon 1. The two exons 1 (1a and 1b) are mutually exclusive and both are spliced to exon 2. This makes the structure of the 5' region of the human CD45 gene identical to its mouse homologue.
Assuntos
Íntrons , Antígenos Comuns de Leucócito/genética , Regiões Promotoras Genéticas , Animais , Sequência de Bases , Galinhas/genética , Sequência Conservada , Regulação da Expressão Gênica , Genes Reporter , Humanos , Camundongos/genética , Dados de Sequência Molecular , Transcrição Gênica , Células Tumorais CultivadasRESUMO
SCID is a heterogeneous group of hereditary diseases. Mutations in the common gamma-chain (gamma(c)) of cytokine receptors, including those for IL-2, IL-4, IL-7, IL-9, and IL-15, are responsible for an X-linked form of the disease, while mutations of several other genes, including Janus-associated kinase-3, may cause autosomal recessive forms of SCID. We investigated the first SCID patient to be described with minimal cell surface expression of the leukocyte common (CD45) Ag. CD45 is an abundant transmembrane tyrosine phosphatase, expressed on all leukocytes, and is required for efficient lymphocyte signaling. CD45-deficient mice are severely immunodeficient and have very few peripheral T lymphocytes. We report here that a homozygous 6-bp deletion in the gene encoding CD45 (PTPRC, gene map locus 1q31-32), which results in a loss of glutamic acid 339 and tyrosine 340 in the first fibronectin type III module of the extracellular domain of CD45, is associated with failure of surface expression of CD45 and SCID. Molecular modeling suggests that tyrosine 340 is crucial for the structural integrity of CD45 protein. This is the second description of a clinically relevant CD45 mutation, provides direct evidence for the importance of CD45 in immune function in humans, and suggests that abnormalities in CD45 expression are a possible cause of SCID in humans.
Assuntos
Antígenos Comuns de Leucócito/genética , Deleção de Sequência/imunologia , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Células CHO , Linhagem Celular , Membrana Celular/genética , Membrana Celular/imunologia , Membrana Celular/metabolismo , Cricetinae , Feminino , Fibronectinas/genética , Ácido Glutâmico/genética , Humanos , Lactente , Antígenos Comuns de Leucócito/biossíntese , Antígenos Comuns de Leucócito/química , Camundongos , Dados de Sequência Molecular , Polimorfismo Genético , Estrutura Terciária de Proteína/genética , Imunodeficiência Combinada Severa/diagnóstico , Imunodeficiência Combinada Severa/etnologia , Transfecção , Células Tumorais Cultivadas , Tirosina/química , Tirosina/genéticaRESUMO
We have applied a sensitive global analysis of TCR heterogeneity to compare clonal dynamics of CD4(+) and CD8(+) T cells in acute infectious mononucleosis. Using this approach, we are able to identify a broad representation of the total virus-specific population without the bias of in vitro culture and then to track their phenotype and fate by their unique molecular footprint. We demonstrate a large number of Ag-driven clones using different TCRs in the acute phase, all CD8(+). The diverse large clones generated in the CD8 subset in response to this virus contrast with the complete lack of detectable clonal expansion in the CD4 compartment. Many of the same clones remain detectable in directly ex vivo CD8(+) T cells for at least a year after resolution of infectious mononucleosis, although the clone size is reduced. Thus, memory CD8 cells following EBV infection persist at relatively high circulating frequency and represent a subset of the large range of clonotypes comprising the acute effectors. Separation of samples into CD45RA (naive) and CD45RO (memory) fractions shows the accumulation of identical CDR3 region defined clonotypes in both CD45RO and CD45RA fractions and sequencing confirms that dominant long-lived monoclonal expansions can reside in the CD45RA pool.