RESUMO
Type 1 diabetes results from chronic autoimmune destruction of insulin-producing ß-cells within pancreatic islets. Although insulin is a critical self-antigen in animal models of autoimmune diabetes, due to extremely limited access to pancreas samples, little is known about human antigenic targets for islet-infiltrating T cells. Here we show that proinsulin peptides are targeted by islet-infiltrating T cells from patients with type 1 diabetes. We identified hundreds of T cells from inflamed pancreatic islets of three young organ donors with type 1 diabetes with a short disease duration with high-risk HLA genes using a direct T-cell receptor (TCR) sequencing approach without long-term cell culture. Among 85 selected CD4 TCRs tested for reactivity to preproinsulin peptides presented by diabetes-susceptible HLA-DQ and HLA-DR molecules, one T cell recognized C-peptide amino acids 19-35, and two clones from separate donors responded to insulin B-chain amino acids 9-23 (B:9-23), which are known to be a critical self-antigen-driving disease progress in animal models of autoimmune diabetes. These B:9-23-specific T cells from islets responded to whole proinsulin and islets, whereas previously identified B:9-23 responsive clones from peripheral blood did not, highlighting the importance of proinsulin-specific T cells in the islet microenvironment.
Assuntos
Autoantígenos/imunologia , Linfócitos T CD4-Positivos/imunologia , Diabetes Mellitus Tipo 1/imunologia , Insulina/imunologia , Ilhotas Pancreáticas/imunologia , Fragmentos de Peptídeos/imunologia , Proinsulina/imunologia , Precursores de Proteínas/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Adolescente , Peptídeo C/imunologia , Criança , Feminino , Antígenos HLA-DQ/imunologia , Antígenos HLA-DR/imunologia , Humanos , Células Secretoras de Insulina , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/patologia , Receptores de Antígenos de Linfócitos T/genética , Adulto JovemAssuntos
Diabetes Mellitus Tipo 1/cirurgia , Transplante das Ilhotas Pancreáticas/métodos , Células de Sertoli/transplante , Transplante Heterólogo , Animais , Peptídeo C/imunologia , Peptídeo C/metabolismo , Ensaios Clínicos como Assunto , Humanos , Masculino , México , Células de Sertoli/fisiologia , SuínosRESUMO
Para estudiar la presentación clínica y criterios de clasificación de la diabetes mellitus tipo I (DMI) en el anciano diabético (AD), se investigaron 258 pacientes diabéticos con más de 60 años, de los cuales 40 por ciento usaba insulina por haber fracasado el uso de hipoglicemiantes orales (HO). La prevalencia de cardiopatía isquémica fue 36 por ciento, enfermedad vascular periférica 34 por ciento y accidentes cerebro vasculares 30 por ciento; un 47 por ciento presentó retinopatía no-proliferativa, 37 por ciento neuropatía periférica simétrica y 16 por ciento nefropatía con una duración promedio de diabetes de 20 años. El 36 por ciento fueron obesos (IMC>25), 33 por ciento tuvieron hipertensión arterial y 12 por ciento dislipidemia. Péptido-C basal y post glucagon, antígenos HLA-DR y anticuerpos anti islote pancreático (ICA), fueron medidos en 75 AD en tratamiento, de los cuales 24 usaban insulina, 40 HO y 11 sólo dieta. Los AD en insulina, tuvieron un largo período de enfermedad, menos obesidad, niveles basales disminuídos de Péptido-C y baja respuesta de Péptido-C post glucagon (0.94 +/- 0.5 pmol/ml), en comparación con los tratados sólo con dieta (1.8 +/- 0.9 pmol/ml) y en HO (1.8 +/- 0.8 pmol/ml). Los ancianos diabéticos en insulino terapia tuvieron una mayor frecuencia de Ag HLA-DR3 (42 por ciento) y Ag HLA-DR4 (21 por ciento). Los ICA fueron negativos excepto en 2 pacientes. El presente estudio demuestra la alta prevalencia de enfermedad macrovascular y microvascular en los pacientes ancianos con diabetes mellitus y que el parámetro más confiable para caracterizar la insulinodependencia en éste grupo de edad, es la medición del Péptido-C basal y post glucagon. Los marcadores inmunogenéticos Ag HLA-DR e ICA, pueden ser utilizados concomitantemente, para ayudar a clasificar DMI en el anciano é instaurar un tratamiento insulínico racional
Assuntos
Humanos , Pessoa de Meia-Idade , Diabetes Mellitus Tipo 1/classificação , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/terapia , Peru , Diabetes Mellitus/complicações , Diabetes Mellitus/imunologia , Diabetes Mellitus/patologia , Dietoterapia/tendências , Dietoterapia , Dietoterapia/estatística & dados numéricos , Peptídeo C/isolamento & purificação , Peptídeo C , Peptídeo C/imunologia , Peptídeo C/sangue , Peptídeo CRESUMO
Protocols were evaluated in an attempt to produce human monoclonal antibodies (HumAb) specific for the human immunodeficiency virus type 1 (HIV-1). The first series of experimentls involved in vitro immunization of normal human peripheral blood lymphocytes (PBL) with peptide C57 (HIV-1 strain IIIB clone BH10 gp 120 amino acids 324-338: GNMRQAHCNISRAKW) followed by either fusion to mouse/human heterolhybrids or transformation with Epstein Barr virus (EBV). Using the hybridoma technology, three IgM class (alfa light chain) Human Ab were obtained. In a parallel study, PBL from two HIV-1 infected patients were immortalized after in vitro stimulation with fragments of the HIV-1 envelope glycoprotein (recombinant gp120 fragment of gp 120, amino acids 295-473, or the penv9 fragment of gp160, amino acids 474-757). Five IgG class Human b (three IgG2m alfa; one IgG1, K; one IgG3, alfa) reactive with the antigens used in the in vitro stimulations were obtained
Assuntos
Humanos , Anticorpos Monoclonais/biossíntese , Peptídeo C/imunologia , HIV-1/imunologia , Técnicas In Vitro , Linfócitos/fisiologia , Sequência de Aminoácidos , Imunização , /imunologiaRESUMO
The extent and the clinical significance of residual beta cell function has been evaluated by radioimmunoassay of C-peptide in 41 diabetic children in different stages of evolution, using an arginine tolerance test. In control subjects a significant rise of C-peptide levels occurred after the infusion with arginine. In patients at the onset of the disease and in patients not in the remission stage, C-peptide levels showed no increment and basal values were significantly lower than in healthy control children. Children during the remission phase showed basal and peak values not significantly different from controls. A positive correlation was found between highest CPR levels compared to basal CPR values and to the age at onset of diabetes; a negative correlation was found between the duration of the disease and insulin requirement.