The aim of the present study was to develop a dendritic cell (DC) vaccine encoding hepatitis C virus (HCV) multiple cytotoxic T lymphocyte (CTL) epitopes that can stimulate T cell responses in vitro, and can be used for immunization in vivo. DCs were infected with recombinant replication-defective adenoviruses (Ads) expressing 2 HCV sequences fused with green fluorescent protein (GFP) and FLAG tags. One sequence (sequence 1) contained the HCV CTL epitopes, NS4B 1793-1801 and P7 774-782, as well as the HCV Th epitope, NS3 1248-1261. A second sequence (sequence 2) was the positive epitope control which contained HCV core 35-44, core 132-140 and NS3 1248-1261. The efficiency of infection was detected by flow cytometry and the expression of HCV epitopes in the DCs was confirmed by RT-PCR and western blot analysis. Ad infection significantly enhanced DC maturation and interleukin (IL)-12p70 production, resulting in T cell proliferation and increased interferon-γ secretion. The CTLs stimulated by Ad-infected DCs specifically killed Huh7.5 human hepatoma cells. The recombinant Ad-expressing multiple CTL HCV epitopes effectively infected the DCs in vitro and promoted T cell antiviral immune responses, thereby laying the foundation for the development of anti-HCV DC vaccines.

T cell dysfunction has a crucial role in establishing and maintaining viral persistence. We have previously shown a decline in miR-181a, which regulates CD4+ T cell responses via DUSP6 overexpression, in individuals with hepatitis C virus (HCV) infection. Here, we describe accelerated T cell senescence in HCV-infected individuals compared with age-and sex-matched healthy subjects. Mechanistic studies revealed that up-regulation of transcription factor ∆Np63 led to the decline of miR-181a expression, resulting in an overexpression of the antiaging protein Sirt1, in CD4+ T cells from HCV-infected individuals. Either reconstituting miR-181a or silencing ∆Np63 or Sirt1 expression in CD4+ T cells led to accelerated T cell senescence, as evidenced by an increased senescence-associated b-galactosidase (SA-β-gal) expression, shortened telomere length, and decreased EdU incorporation; this suggests that HCV-induced T cell senescence is counterregulated by the ∆Np63-miR-181a-Sirt1 pathway. An increase of IL-2 production was observed in these senescent CD4+ T cells and was driven by a markedly reduced frequency of Foxp3+ regulatory T (Treg) cells and increased number of Foxp3- effector T (Teff) cells upon manipulating the ∆Np63-miR-181a-Sirt1 pathway. In conclusion, these findings provide novel mechanistic insights into how HCV uses cellular senescent pathways to regulate T cell functions, revealing new targets for rejuvenating impaired T cell responses during chronic viral infection.

Hepatitis C virus (HCV) infection is a global health problem characterized by a high rate of chronic infection, which may in part be due to a defect in myeloid dendritic cells (mDCs). This defect appears to be remedied by treatment with interferon-α (IFN-α) -based antiviral therapies; however, the molecular mechanisms underlying mDC dysfunction in HCV infection and restoration by IFN-α treatment are unclear. The ubiquitin-editing protein A20 plays a crucial role in controlling the maturation, cytokine production and immunostimulatory function of mDCs. We propose that the expression of A20 correlates with the function of mDCs during HCV infection and IFN-α therapy. In this study, we observed that A20 expression in mDCs isolated from chronically HCV-infected subjects was significantly higher than healthy subjects or subjects achieving sustained virological responses (SVR) following antiviral treatment. Notably, A20 expression in mDCs from HCV patients during IFN-α treatment was significantly lower than for untreated patients, SVR patients, or healthy subjects. Besides, A20 expression in mDCs stimulated by polyI:C differed between HCV patients and healthy subjects, and this difference could be abrogated by the treatment with IFN-α in vitro. Additionally, A20 expression by polyI:C-activated mDCs, with or without IFN-α treatment, negatively correlated with the expression of HLA-DR, CD86 and CCR7, and the secretion of interleukin-12 (IL-12), but positively associated with the production of IL-10. Importantly, silencing A20 expression using small interfering RNAs increased the production of IL-12 in mDCs of chronically HCV-infected individuals. These findings suggest that A20 plays a crucial role in negative regulation of innate immune responses during chronic viral infection.

Hepatitis C virus (HCV) is remarkably efficient at evading host immunity to establish chronic infection. During chronic HCV infection, interleukin-12 (IL-12) produced by monocytes/macrophages (M/Mφ) is significantly suppressed. Programmed death-1 (PD-1), an inhibitory receptor on immune cells, plays a pivotal role in suppressing T-cell responses during chronic viral infection. To determine whether PD-1 regulates IL-12 production by M/Mφ during chronic HCV infection, we examined the expressions of PD-1, its ligand PDL-1, and their relationship with IL-12 production in M/Mφ from HCV-infected, HCV-resolved, and healthy subjects by flow cytometry. Toll-like receptor (TLR) -mediated IL-12 production by M/Mφ was selectively suppressed, while PD-1/PDL-1 expressions were up-regulated, in HCV-infected subjects compared with HCV-resolved or healthy subjects. Up-regulation of PD-1 was inversely associated with the degree of IL-12 inhibition in HCV infection. Interestingly, the reduced response of M/Mφ from HCV-infected individuals to TLR ligands appeared not to be the result of a lack of the ability to sense pathogen, but to an impaired activation of intracellular janus kinase/signal transducer and activator of transfection (STAT) pathway as represented by inhibited STAT-1 phosphorylation in M/Mφ from HCV-infected individuals compared with HCV-negative subjects. Successful HCV treatment with pegylated interferon/ribavirin or blocking PD-1/PDL-1 engagement ex vivo led to reduced PD-1 expression and improved IL-12 production as well as STAT-1 activation in M/Mφ from HCV-infected individuals. These results suggest that the PD-1 inhibitory pathway may negatively regulate IL-12 expression by limiting STAT-1 phosphorylation in M/Mφ during chronic HCV infection. No claim to original US government works.

Hepatitis C virus (HCV) is a positive strand RNA virus that is the leading cause of chronic hepatitis. HCV infections are an important health problem because >80% of patients become chronically infected and many develop chronic hepatitis. With approximately 400 million chronic HCV infections worldwide, understanding the pathogenesis of this disease is of critical importance in order to develop appropriate therapies and/or vaccine strategies. Strong proliferative and cytotoxic T cell responses that target multiple HCV proteins are detected in patients with self-limited infection. Conversely, HCV-specific T cell responses are minimal during acute infection in patients who become chronically infected. It is thought that the genetic diversity of HCV plays a crucial role in establishing persistence. Chronic viral hepatitis is characterized by infiltration of T lymphocytes in the liver, which are thought to play a pivotal role in disease progression. Although virus-specific T cells can be isolated from both peripheral blood and from liver biopsy samples of chronically infected patients, there appears to be a compartmentalization of HCV-specific T cells in the liver. However, the presence of virus-specific T cells is inefficient for viral clearance. Because HCV is known to be highly variable in sequence, the detailed characterization of the interaction of individual HCV-specific CTL clones with autologous viral sequences might be important for understanding the mechanisms by which HCV is able to establish a chronic infection. We isolated three intrahepatic CD8+ CTL clones from two individuals with chronic HCV infection and compared the recognition of prototype and autologous HCV sequences. These CTL recognized epitopes within the NS2 (amino acids 957-964) or NS3 (amino acids 1402-1410 and 1406-1415) proteins in the context of HLA B37, B8, or A2.1, respectively. The corresponding predominant autologous HCV sequences (SDWAANGL, ELAAKLVGL, ALRGMGLNAV, respectively) differed from the HCV-1 prototype sequences used for screening (RDWAHNGL, ELAAKLVAL, KLVALGINAV, respectively) at one to five residues. For each CTL clone, recognition of the autologous HCV sequence required significantly higher peptide concentrations than did recognition of the HCV-1 sequence; for two of the clones, recognition was minimal or absent at peptide concentrations as high as 25μM. When the HLA A2.1-restricted HCV NS3-specific T cell clone was analyzed further, we found that it was cross-reactive with peptide sequences from at least three other HCV strains. The clone recognized target cells loaded with synthetic peptides derived from sequences of genotype 1b; HCVTW (KLSALGIHAV), HCVJA (KLTGLGLNAV),and HCVBK (KLSGLGINAV). This HCV-specific T cell clone was also able to recognize target cells that were loaded with a peptide derived from an autologous protein, cellular retinoic acid binding protein I (CRABP I). When we generated HLA A2.1-restricted HCV NS3-specific T cell lines from the peripheral blood of two additional patients, almost one half of the cell lines could lyse target cells loaded with the CRABP I peptide. These data show that intrahepatic HCV-specific CD8+ CTL clones can be relatively inefficient at recognizing autologous viral epitopes and that some viral-specific CTL can recognize autoantigens in vitro. There is little information regarding the composition and stability of the liver-infiltrating T cell repertoire during chronic HCV infection. To address this issue, we used TCR complimentarity determining region 3 (CDR3) length analysis to examine the T lymphocytes in sequential biopsy samples from five individuals chronically infected with HCV. We found that although almost all TCRBV families were represented in the liver, 25-85% had skewed spectratype profiles, indicative of the presence of clonally expanded T cells. Further analysis using TCRBJ-primed run-off reactions revealed that the intrahepatic repertoires were not stable, as many expansions that existed in one biopsy sample were not detected in the other. Some expansions persisted, however, and sequencing of TCRBV-J transcripts identified CDR3 sequences that were maintained in two individuals for 10 or 45 months. Furthermore, although some expansions were found in the periphery, most were represented only in the liver. These data suggest that there is an evolution of the immune response during chronic HCV infection and that the response is largely concentrated in the liver of these individuals. Based on our observations regarding the function of intrahepatic HCV-specific CTL and the dynamics of the intrahepatic repertoire during chronic HCV infection, we propose a model in which the co-evolution of HCV quasispecies and HCV-specific T cells contribute to both viral persistence and immunopathology.

No description available.

La investigación busca medir la producción de anticuerpos anti-HBs al 1, 2 y 6 meses, evaluar la seroconversión y seroprotección en ambos grupos; cultivar células mononucleares de sangre periférica para el estudio de la producción de óxido nítrico (NO), comparar el recuento diferencial de la población de linfocitos CD3+CD4+ (LT cooperadores) y CD3+CD8+ (LT citotóxicos) y finalmente realizar un hemograma a todos los voluntarios al mes y a los 2 meses de iniciado el tratamiento para el recuento de leucocitos, eritrocitos, neutrófilos, linfocitos, basófilos, eosinófilos y monocitos; así como también determinar los niveles de hemoglobina. La Lepidium peruvianum Chacón (Brassicaceae), también conocida como maca, es una planta medicinal que crece exclusivamente entre 4,000 y 4,500 msnm en los Andes del Perú, presenta diferentes ecotipos que varían de acuerdo al color de la raíz, que va desde el blanco al negro; en la actualidad es ampliamente usada por sus importantes propiedades nutritivas y medicinales relacionadas con la presencia de diversos metabolitos secundarios. Para evaluar el efecto del tratamiento con maca sobre la respuesta inmune tanto humoral como celular se inmunizaron 70 personas voluntarias adultas y sanas con la vacuna contra el virus de la hepatitis B, Gene Vac B. Se formaron 2 grupos, uno se trató con maca pulverizada (3g/día) y el control fue tratado con placebo. Se aplicó un estudio aleatorio a doble ciego, todos los participantes recibieron las tres dosis de la vacuna de acuerdo al esquema de vacunación (0, 1, 6 meses) y durante 2 meses contados a partir de la primera dosis ambos grupos recibieron una dosis diaria de maca y placebo respectivamente. / Tesis

Les maladies auto-immunes résultent d’un dysfonctionnement du système immunitaire. L’étiologie de la pathologie reste souvent inconnue, compliquant la conception de traitements adaptés. Ce projet de thèse s’est focalisé sur la molécule « a proliferation inducing ligand » (APRIL), facteur de survie des plasmocytes (PC) produisant les anticorps, dans l’hépatite auto-immune (HAI) et la sclérose en plaques (SEP). Dans l’HAI, une principale caractéristique histologique est la présence d’un infiltrat lymphoplasmocytaire formant une hépatite d’interface dommageable. Dans cette maladie, nous avons d’abord pu mettre en évidence une corrélation positive entre l’expression d’APRIL et l’infiltration des PC dans les espaces portes. In vitro, nous avons observé une survie augmentée des PC du foie en présence d’APRIL. La corticothérapie communément prise par les patients HAI ne cible pas directement les PC. Cependant, nous avons remarqué une réduction simultanée de la densité de PC et de l’expression d’APRIL. Ainsi, cette étude étend le rôle de facteur de survie d’APRIL aux PC du foie dans l’HAI. Les rechutes sont fréquentes après arrêt du traitement, nous indiquant que les cellules pathogènes sont épargnées par la thérapie. Nos résultats montrent que le ciblage d’APRIL pourrait être précieux dans l’HAI. Propre de son rôle sur les PC, APRIL a été ciblée avec succès dans plusieurs maladies auto-immunes. Outre ces succès, un essai clinique visant à bloquer APRIL dans la SEP à malheureusement conduit à une exacerbation inattendue de la maladie. Nous avons été capables de montrer qu’APRIL cible un nouveau type cellulaire dans le système nerveux central, les astrocytes. La fixation d’APRIL à la surface des astrocytes dépend d’un nouveau partenaire de liaison, exprimé par ces derniers, les chondroïtines sulfates protéoglycans. Cette interaction induit la production de la cytokine anti-inflammatoire IL-10, conduisant à l’inhibition de, la prolifération des lymphocytes T auto-réactifs et la sécrétion de cytokines pro-inflammatoires. L’utilisation de souris déficientes pour APRIL dans le modèle standard de la SEP nous a permis de confirmer le rôle neuro-protecteur d’APRIL. Finalement, après injection d’APRIL recombinante dans ce modèle murin, une réduction de la sévérité de la maladie a été observée. Globalement, nous avons identifié APRIL comme une molécule à double rôle dans les maladies auto-immunes. / Autoimmune diseases result from a dysfunction of the immune system. The disease etiology is often unknown, complicating the design of appropriate treatments. This thesis project focused on the molecule “a proliferation inducing ligand” (APRIL), a survival factor for antibody-producing plasma cells (PC), in autoimmune hepatitis (AIH) and multiple sclerosis (MS). In AIH, one main histological feature is the presence of a lymphoplasmacytic infiltration forming a damaging interface hepatitis. In this disease, we first noticed a positive correlation between APRIL expression and PC infiltration in portal spaces. In vitro, we further observed an extended survival of liver PC in the presence of APRIL. The corticosteroid therapy commonly applied to AIH patients does not directly target PC. However, we noticed a concomitant reduction in portal PC density and APRIL expression. Hence, this study is extending the survival role of APRIL to liver PC in AIH. Relapses are frequent after treatment withdrawal, telling us that pathogenic cells are spared by the therapy. Our results indicate that APRIL targeting might also be valuable in AIH. Own to its role on PC, APRIL has been successfully targeted in several autoimmune diseases. Besides successes, a clinical trial aiming at APRIL blockade in MS has unfortunately led to an unexpected disease exacerbation. We have been able to show that APRIL targets a new cell type in the central nervous system, the astrocyte. The APRIL binding to astrocyte surface depends on a new binding partner, expressed by the latter, the chondroitin sulfate proteoglycans. This binding induces the production of the anti-inflammatory cytokine IL-10, leading to the inhibition of, self-reactive T-cell proliferation and pro-inflammatory cytokine secretion. Use of APRIL-deficient mice in the standard model of MS allowed us to confirm the neuroprotective role of APRIL. Finally, after recombinant APRIL injection in this model, a lowered disease severity was observed. Overall, we identified APRIL as a dual role molecule in autoimmune diseases.

Publicación a texto completo no autorizada por el autor / Identifica los genotipos circulantes del VHC en el Perú durante el periodo 2010 – 2012. Se realiza un estudio exploratorio descriptivo. Se identifican 52 muestras con serología reactiva e indeterminada a anticuerpos anti-VHC, se utiliza el kit INNOTEST® HCV Ab, y se realiza la confirmación con un inmunoblot INNO-LIATM HCV Score, ambos kits de la marca INNOGENETICS®. Sólo se procesan 44 muestras mediante varias pruebas de PCR con diferentes juegos de cebadores dirigidos a la región NS5b y Core. El secuenciamiento es realizado por el método de Sanger, se utilizan secuencias de referencia del GenBank para la limpieza, alineamiento y construcción del árbol filogenético. Las secuencias se analizan con los programas ClustalX, Sequencher v.5.4.1, BioEdit y Mega v.6. / Tesis

Caracteriza el perfil clínico-epidemiológico de los pacientes con insuficiencia hepática aguda en el Instituto Nacional de Salud del Niño, 2011- 2018. Es un estudio descriptivo transversal de tipo retrospectivo. La población conformada por pacientes de 0 meses a 18 años del INSN con diagnóstico de IHA durante los años 2011-2018. En las variables cualitativas se calculó la frecuencia; y en las variables cuantitativas, promedios y desviación estándar. En el análisis bivariado se calculó el Odds ratio, el intervalo de confianza al 95% y el valor p. La población total fue de 76 pacientes, el sexo masculino representó 67% de los pacientes, la edad promedio 6 años y el 57.9 % procedencia Lima. Las etiologías más frecuentes fueron infecciosa (46.1%) e indeterminada (23.7%), y la infección por hepatitis A representó el 37.9%. Se encontraron en etapa aguda de IHA el 48.7%, encefalopatía Grado I el 44.7 %, ictericia en el 98.7%, no presentó ascitis el 67.1%, no presentó ninguna complicación 42.1%, no requirió de trasplante el 84% de pacientes. Se concluye que la etiología y patología más frecuente fue la infecciosa y Hepatitis A respectivamente. La frecuencia de mortalidad fue del 32%. Se encontró que las variables; peso, etiología infecciosa, encefalopatía, albumina, TGP y hemoglobina están asociados a riesgo de mortalidad; mientras que las variables; complicación, el requerimiento de trasplante, INR, TP, urea, leucocitos, plaquetas, creatinina, sodio sérico y cloro sérico se relacionan con mejor pronóstico. / Tesis