RESUMEN
INTRODUCTION: Streptococcus agalactiae, also known as group B streptococci (GBS), is associated with invasive infections in neonates. Identification of GBS vaginal colonization in pregnant women before delivery is essential for treatment with antibiotics to prevent intrapartum vertical transmission to the newborn. This study was designed to evaluate applicability of two rapid real-time PCRs in comparison to standard culture identification. MATERIAL AND METHODS: We compared the Xpert GBS assay, hereafter referred to as Xpert, and GenomEra GBS PCR, hereafter referred to as GenomEra. The standard culture identification consisted of two different agar plates as well as an enrichment broth. RESULTS: We analyzed vaginal samples of 260 pregnant women; 42 samples were tested GBS-positive by using standard culture as a gold standard, 30 by Xpert, and 37 by GenomEra. Xpert and GenomEra assays performed with sensitivities of 71.4% and 88.1% as well as specificities of 98.6% and 99.1%, respectively. Twelve vaginal samples were false-negative by Xpert and five samples by GenomEra. Interestingly, three negative Xpert results of standard culture-positive samples exhibited high Ct-values indicating the presence of GBS. If higher Ct-values are taken into consideration, the sensitivity of Xpert increases up to 78.6%. Moreover, only three Xpert PCRs had to be repeated, whereas two Genomera were invalid even after repetition and further 15 GenomEra PCRs were repeated because of borderline results or inhibition of the PCR test. CONCLUSIONS: In this study, GenomEra assay performed with a higher sensitivity than the Xpert PCR. On the other hand, the Xpert assay needs less hands-on-time for a sample preparation and requires approximately four-fold less repetitions as compared to the GenomEra assay. This robust performance of the Xpert assay make it applicable as a rapid intrapartum point-of-care test, although a higher sensitivity would be desirable. Therefore, culture in the 35-37 week of gestation remains the gold standard to detect vaginal colonization.
Asunto(s)
Infecciones Estreptocócicas , Streptococcus agalactiae , Vagina , Streptococcus agalactiae/genética , Streptococcus agalactiae/aislamiento & purificación , Infecciones Estreptocócicas/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa , Vagina/microbiología , Pruebas en el Punto de Atención , Humanos , Femenino , Adulto , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/microbiología , Embarazo , Recién Nacido , Sensibilidad y EspecificidadRESUMEN
The giant cytosolic protease tripeptidyl peptidase II (TPPII) has been implicated in the regulation of proliferation and survival of malignant cells, particularly lymphoma cells. To address its functions in normal cellular and systemic physiology we have generated TPPII-deficient mice. TPPII deficiency activates cell type-specific death programs, including proliferative apoptosis in several T lineage subsets and premature cellular senescence in fibroblasts and CD8(+) T cells. This coincides with up-regulation of p53 and dysregulation of NF-kappaB. Prominent degenerative alterations at the organismic level were a decreased lifespan and symptoms characteristic of immunohematopoietic senescence. These symptoms include accelerated thymic involution, lymphopenia, impaired proliferative T cell responses, extramedullary hematopoiesis, and inflammation. Thus, TPPII is important for maintaining normal cellular and systemic physiology, which may be relevant for potential therapeutic applications of TPPII inhibitors.
Asunto(s)
Envejecimiento/inmunología , Apoptosis/inmunología , Serina Endopeptidasas/deficiencia , Serina Endopeptidasas/metabolismo , Aminopeptidasas , Animales , Diferenciación Celular/inmunología , Células Cultivadas , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas , Fibroblastos , Eliminación de Gen , Linfopenia/enzimología , Linfopenia/genética , Linfopenia/patología , Ratones , Ratones Noqueados , FN-kappa B/metabolismo , Fenotipo , Serina Endopeptidasas/genética , Linfocitos T/citología , Linfocitos T/enzimología , Linfocitos T/inmunología , Timo/citología , Timo/enzimología , Timo/inmunología , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
Endoplasmic reticulum-associated aminopeptidase 1 (ERAP1) is involved in the final processing of endogenous peptides presented by MHC class I molecules to CTLs. We generated ERAP1-deficient mice and analyzed cytotoxic responses upon infection with three viruses, including lymphocytic choriomeningitis virus, which causes vigorous T cell activation and is controlled by CTLs. Despite pronounced effects on the presentation of selected epitopes, the in vivo cytotoxic response was altered for only one of several epitopes tested. Moreover, control of lymphocytic choriomeningitis virus was not impaired in the knockout mice. Thus, we conclude that lack of ERAP1 has little influence on antiviral immunohierarchies and antiviral immunity in the infections studied. We also focused on the role of ERAP1 in cross-presentation. We demonstrate that ERAP1 is required for efficient cross-presentation of cell-associated Ag and of OVA/anti-OVA immunocomplexes. Surprisingly, however, ERAP1 deficiency has no effect on cross-presentation of soluble OVA, suggesting that for soluble exogenous proteins, final processing may not take place in an environment containing active ERAP1.
Asunto(s)
Aminopeptidasas/inmunología , Presentación de Antígeno/inmunología , Infecciones por Arenaviridae/inmunología , Retículo Endoplásmico/inmunología , Virus de la Coriomeningitis Linfocítica/inmunología , Linfocitos T Citotóxicos/inmunología , Aminopeptidasas/deficiencia , Animales , Presentación de Antígeno/genética , Complejo Antígeno-Anticuerpo/genética , Complejo Antígeno-Anticuerpo/inmunología , Infecciones por Arenaviridae/genética , Reacciones Cruzadas/genética , Reacciones Cruzadas/inmunología , Retículo Endoplásmico/genética , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Virus de la Coriomeningitis Linfocítica/genética , Ratones , Ratones Noqueados , Antígenos de Histocompatibilidad MenorRESUMEN
The expression of housekeeping and/or immunoproteasomes in isolated thymic stroma subsets has so far not been analyzed but may have important consequences for self peptide repertoires presented by MHC class I molecules during positive and negative thymic selection. Here we determined the expression of housekeeping and immunoproteasome beta subunits and of PA28 in positively and negatively selecting stroma subsets. Positively selecting cortical thymic epithelial cells (cTEC) expressed only housekeeping but no immunoproteasome beta subunit mRNA and proteins. However, immunoproteasome beta subunits could be induced in cTEC by infection with Listeria monocytogenes or injection of IFN-gamma. In negatively selecting stroma including medullary epithelial cells and dendritic cells, incomplete and low representation of housekeeping beta subunit proteins but high and complete expression of immunoproteasome beta subunit proteins suggests absence of proper housekeeping proteasomes and predominance of immunoproteasomes. Expression of immunoproteasome beta subunits in negatively selecting stroma was independent of IFN-gamma receptor as shown in knockout (KO) mice. Absence of LMP2 altered thymic selection of the MHC class I-restricted transgenic P14 TCR in KO mice. The data suggest that negative selection may primarily involve immunoproteasome peptide repertoires and that peripheral infection may influence peptide repertoires involved in positive selection.