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1.
Nature ; 443(7108): 218-21, 2006 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-16957736

RESUMO

The insulin receptor is a phylogenetically ancient tyrosine kinase receptor found in organisms as primitive as cnidarians and insects. In higher organisms it is essential for glucose homeostasis, whereas the closely related insulin-like growth factor receptor (IGF-1R) is involved in normal growth and development. The insulin receptor is expressed in two isoforms, IR-A and IR-B; the former also functions as a high-affinity receptor for IGF-II and is implicated, along with IGF-1R, in malignant transformation. Here we present the crystal structure at 3.8 A resolution of the IR-A ectodomain dimer, complexed with four Fabs from the monoclonal antibodies 83-7 and 83-14 (ref. 4), grown in the presence of a fragment of an insulin mimetic peptide. The structure reveals the domain arrangement in the disulphide-linked ectodomain dimer, showing that the insulin receptor adopts a folded-over conformation that places the ligand-binding regions in juxtaposition. This arrangement is very different from previous models. It shows that the two L1 domains are on opposite sides of the dimer, too far apart to allow insulin to bind both L1 domains simultaneously as previously proposed. Instead, the structure implicates the carboxy-terminal surface of the first fibronectin type III domain as the second binding site involved in high-affinity binding.


Assuntos
Dobramento de Proteína , Receptor de Insulina/química , Receptor de Insulina/metabolismo , Cristalografia por Raios X , Dimerização , Fragmentos Fab das Imunoglobulinas/imunologia , Microscopia Eletrônica , Modelos Moleculares , Estrutura Quaternária de Proteína , Estrutura Terciária de Proteína , Receptor de Insulina/imunologia , Receptor de Insulina/ultraestrutura
2.
J Clin Virol ; 36(1): 68-71, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16426889

RESUMO

BACKGROUND: Dried blood spots (DBS) provide a convenient method for blood sample collection in many settings where the prevalence of infection with hepatitis C virus (HCV) is increasing. Consequently, HCV assays are required that produce reliable results using samples derived from DBS. OBJECTIVES AND STUDY DESIGN: The optimum buffer for the elution of samples from DBS was selected and the performance of a commercial enzyme immunoassay (EIA) was evaluated using these DBS eluates and paired plasma samples. RESULTS: DBS with paired plasma samples were compared using this modified commercial EIA, which was found to have an estimated sensitivity and specificity of approximately 100% for detecting anti-HCV antibodies in DBS. CONCLUSION: A DBS-based assay for the detection of antibodies to HCV will prove valuable for collecting epidemiological data in the field or in under resourced settings.


Assuntos
Coleta de Amostras Sanguíneas/métodos , Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/sangue , Hepatite C/sangue , Soluções Tampão , Estudos de Casos e Controles , Estudos de Coortes , Estudos de Avaliação como Assunto , Estudos de Viabilidade , Hepatite C/imunologia , Hepatite C/virologia , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Técnicas Imunoenzimáticas/instrumentação , Técnicas Imunoenzimáticas/métodos , Sensibilidade e Especificidade
3.
AIDS ; 18(17): 2253-9, 2004 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-15577537

RESUMO

OBJECTIVE: To identify a specific marker of recent HIV-1 infection. DESIGN: The humoral immune response in individuals recently infected with HIV-1 was followed by analysing the antibody isotype-specific response generated to HIV-1 antigens in sequential samples collected during and following seroconversion. METHODS: Antibody isotype-specific HIV-1 Western blots were analysed to identify interactions indicative of recent HIV-1 infection. These responses were further quantified using an antibody isotype-specific enzyme-linked immunoabsorbent assay based on recombinant HIV-1 antigens. RESULTS: During maturation of the immune response to HIV-1 infection, a rapid and enduring IgG1 isotype response was seen to all the major proteins transcribed by env, gag and pol. An early transient peak of IgG3 reactivity to p24 was observed over an interval of approximately 1-4 months following HIV-1 infection. The presence of IgG3 reactivity to p24 permitted established infection to be distinguished from recently infected individuals during this time period. CONCLUSION: An assay for anti-p24 IgG3 reactivity would provide an estimate of the incidence of HIV infection that may be applicable for epidemiological surveys as well as for monitoring new infections during vaccine trials and for managing treatment programmes.


Assuntos
Infecções por HIV/imunologia , HIV-1/imunologia , Doença Aguda , Anticorpos Antivirais/imunologia , Especificidade de Anticorpos/imunologia , Reações Antígeno-Anticorpo/imunologia , Antígenos Virais/imunologia , Biomarcadores/sangue , Western Blotting/métodos , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática/métodos , Proteína do Núcleo p24 do HIV/imunologia , Infecções por HIV/epidemiologia , Humanos , Imunoglobulina G/análise , Sensibilidade e Especificidade , Estudos Soroepidemiológicos
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