Home About us Contact
|
Home About us Contact | ||
|
|
||
Peptide Pool (peptide + pool)
Selected AbstractsInterleukin-10-secreting T cells define a suppressive subset within the HIV-1-specific T-cell populationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2009Eirik A. Torheim Abstract Recent studies have indicated that Treg contribute to the HIV type 1 (HIV-1)-related immune pathogenesis. However, it is not clear whether T cells with suppressive properties reside within the HIV-1-specific T-cell population. Here, PBMC from HIV-1-infected individuals were stimulated with a 15-mer Gag peptide pool, and HIV-1-specific T cells were enriched by virtue of their secretion of IL-10 or IFN-, using immunomagnetic cell-sorting. Neither the IL-10-secreting cells nor the IFN-,-secreting cells expressed the Treg marker FOXP3, yet the IL-10-secreting cells potently suppressed anti-CD3/CD28-induced CD4+ as well as CD8+ T-cell proliferative responses. As shown by intracellular cytokine staining, IL-10- and IFN-,-producing T cells represent distinct subsets of the HIV-1-specific T cells. Our data collectively suggest that functionally defined HIV-1-specific T-cell subsets harbor potent immunoregulatory properties that may contribute to HIV-1-associated T-cell dysfunction. [source] CSF amyloid-, 1-38 and 1-42 in FTD and AD: Biomarker performance critically depends on the detergent accessible fractionPROTEOMICS - CLINICAL APPLICATIONS, Issue 10-11 2008Mirko Bibl Dr. Abstract Cerebrospinal fluid (CSF) A,1-38, A,1-40, and A,1-42 were comparatively analyzed by amyloid-beta SDS-PAGE with Western immunoblot (A,-SDS-PAGE/immunoblot), electrochemiluminescence detection and ELISA (MSD/ELISA) in patients with Alzheimer's disease (AD, n,=,40), frontotemporal dementia (FTD, n,=,30), and other dementias (n,=,50) and nondemented disease controls (n,=,30). CSF A,-peptide concentrations were higher and selective decreases of CSF A,1-38 in FTD and A,1-42 in AD were more evident as measured after SDS-denaturizing of samples by A,-SDS-PAGE/immunoblot. The SDS-accessible pool of CSF A,1-38 and A,1-42, represented by the individual gain of A,-peptide yield using A,-SDS-PAGE/immunoblot, was reduced in both FTD and AD. Accordingly, biomarker accuracies of A,1-38 and A,1-42 for detection of FTD and AD, respectively declined as determined by MSD/ELISA. We conclude that a pool of CSF A,1-38 and A,1-42, which shows disease-specific reductions in FTD and AD, may be bound to carriers and can be released by SDS. Assessing this SDS-accessible A,-peptide pool may crucially enhance the accuracy of CSF biomarker tests. Identifying disease-specific binding properties of affected A, carriers may elucidate pathogenic aspects and open up a novel field for therapeutic approaches. [source] Analysis of the HLA class I associated peptide repertoire in a hepatocellular carcinoma cell line reveals tumor-specific peptides as putative targets for immunotherapyPROTEOMICS - CLINICAL APPLICATIONS, Issue 3 2007Iñaki Alvarez Abstract HLA class I molecules present peptides on the cell surface to CD8+ T cells. The repertoire of peptides that associate to class I molecules represents the cellular proteome. Therefore, cells expressing different proteomes could generate different class I-associated peptide repertoires. A large number of peptides have been sequenced from HLA class I alleles, mostly from lymphoid cells. On the other hand, T cell immunotherapy is a goal in the fight against cancer, but the identification of T cell epitopes is a laborious task. Proteomic techniques allow the definition of putative T cell epitopes by the identification of HLA natural ligands in tumor cells. In this study, we have compared the HLA class I-associated peptide repertoire from the hepatocellular carcinoma (HCC) cell line SK-Hep-1 with that previously described from lymphoid cells. The analysis of the peptide pool confirmed that, as expected, the peptides from SK-Hep-1 derive from proteins localized in the same compartments as in lymphoid cells. Within this pool, we have identified 12 HLA class I peptides derived from HCC-related proteins. This confirms that tumor cell lines could be a good source of tumor associated antigens to be used, together with MS, to define putative epitopes for cytotoxic T cells from cancer patients. [source] Cell-Mediated Immunity to Predict Cytomegalovirus Disease in High-Risk Solid Organ Transplant RecipientsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2009D. Kumar Late-onset cytomegalovirus (CMV) disease commonly occurs after discontinuation of antiviral prophylaxis. We determined the utility of testing CD8+ T-cell response against CMV as a predictor of late-onset CMV disease after a standard course of antiviral prophylaxis. Transplant patients at high-risk for CMV disease were enrolled. CD8+ T-cell-mediated immunity (CMI) was tested using the QuantiFERON-CMV assay at baseline, 1, 2 and 3 months posttransplant by measurement of interferon-, response to whole blood stimulation with a 21-peptide pool. The primary outcome was the ability of CMI testing to predict CMV disease in the first 6 months posttransplant. There were 108 evaluable patients (D+/R+ n = 39; D-/R+ n = 34; D+/R- n = 35) of whom 18 (16.7%) developed symptomatic CMV disease. At the end of prophylaxis, CMI was detectable in 38/108 (35.2%) patients (cutoff 0.1 IU/mL interferon-,). CMV disease occurred in 2/38 (5.3%) patients with a detectable interferon-, response versus 16/70 (22.9%) patients with a negative response; p = 0.038. In the subgroup of D+/R- patients, CMV disease occurred in 1/10 (10.0%) patients with a detectable interferon-, response (cutoff 0.1 IU/mL) versus 10/25 (40.0%) patients with a negative CMI, p = 0.12. Monitoring of CMI may be useful for predicting late-onset CMV disease. [source] Monitoring cytomegalovirus IE-1 and pp65-specific CD4+ and CD8+ T-cell responses after allogeneic stem cell transplantation may identify patients at risk for recurrent CMV reactivations ,CYTOMETRY, Issue 4 2008Jan W. Gratama Abstract We studied the recovery of CMV-specific CD4+ and CD8+ T-cell immunity in 52 recipients of allogeneic stem cell transplantation (SCT). The proportions of IFN-,-producing CD4+ and CD8+ T cells upon in vitro activation using peptide pools representing the CMV pp65 and IE-1 proteins were assessed at multiple time points post SCT, and correlated with the occurrence of CMV reactivation. In a retrospective analysis, recurrent CMV reactivations occurred in 9 patients and were associated with low pp65-specific CD4+ T-cell and low IE-1-specific CD8+ T-cell reactivities, whereas patients without detectable CMV reactivation (n = 30) or a single reactivation (n = 13) showed a better recovery of these immune responses. CD4+ T-cell responses to IE-1 were infrequent in most patients, whereas CD8+ T-cell responses to pp65 occurred frequently, but did not correlate with protection against (recurrent) reactivation. Prospectively, CMV-specific T-cell responses could be studied prior to 14 reactivation episodes in 8 patients. CD4+ T-cell responses to IE-1 and pp65 were positive in only 1 and 2 episodes, respectively. CD8+ T-cell responses against IE-1 were positive in 4, but against pp65 in 12 episodes, again showing that CD8+ T-cell reactivity against pp65 did not prevent CMV reactivation. Thus, monitoring of particular CMV-specific CD4+ and CD8+ T-cell responses after allogeneic SCT may identify patients at risk for recurrent CMV reactivations. © 2008 Clinical Cytometry Society [source] HCV-specific T-cell responses in injecting drug users: evidence for previous exposure to HCV and a role for CD4+ T cells focussing on nonstructural proteins in viral clearanceJOURNAL OF VIRAL HEPATITIS, Issue 6 2008T. A. Ruys Summary., In order to understand the parameters associated with resolved hepatitis C virus (HCV)-infection, we analysed the HCV-specific T-cell responses longitudinally in 13 injecting drug-users (IDUs) with a prospectively identified acute HCV infection. Seven IDUs cleared HCV and six IDUs remained chronically infected. T-cell responses were followed in the period needed to resolve and a comparable time span in chronic carriers. Ex vivo T-cell responses were measured using interferon-, Elispot assays after stimulation with overlapping peptide pools spanning the complete HCV genome. CD4+ memory- T-cell responses were determined after 12-day stimulation with HCV proteins. The maximum response was compared between individuals. The T-cell responses measured directly ex vivo were weak but significantly higher in resolvers compared to chronic carriers, whereas the CD4+ memory -T-cell response was not different between resolvers and chronic carriers. However, HCV Core protein was targeted more often in chronic carriers compared to individuals resolving HCV infection. CD4+ T-cell responses predominantly targeting nonstructural proteins were associated with resolved HCV infection. Interestingly, observation of memory-T-cell responses present before the documented HCV-seroconversion suggests that reinfections in IDUs occur often. The presence of these responses however, were not predictive for the outcome of infection. However, a transition of the HCV-specific CD4+ memory -T-cell response from targeting Core to targeting nonstructural proteins during onset of infection was associated with a favourable outcome. Therefore, the specificity of the CD4+ memory -T-cell responses measured after 12-day expansion seems most predictive of resolved infection. [source] Polyomavirus BK-Specific Cellular Immune Response to VP1 and Large T-Antigen in Kidney Transplant RecipientsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2007S. Binggeli Polyomavirus BK (BKV) is the primary cause of polyomavirus-associated nephropathy (PVAN) in kidney transplant (KT) recipients. Using ELISpot assays, we compared the frequency of interferon-, (IFN-,) secreting peripheral blood mononuclear cells (PBMC) after stimulation with overlapping peptide pools covering BKV large T-antigen (LT) and VP1 capsid proteins (VP1). In 10 healthy donors, LT and VP1 responses were low with median 24 (range 15,95) and 25 (7,113) spot-forming units/106 PBMC (SFU), respectively. In 42 KT patients with current or recent plasma BKV loads, median LT and VP1 responses of 29 (0,524) and 114 (0,1432) SFU were detected, respectively. In KT patients with decreasing or past plasma BKV loads, significantly higher median BKV-specific IFN-, responses were detected compared to KT patients with increasing or persisting BKV loads [LT: 78 (8,524) vs. 22 (0,120) SFU, p = 0.003; VP1: 285 (45,1432) vs. 53 (0,423) SFU, p = 0.001, respectively]. VP1-specific IFN-, responses were higher and more likely to involve CD4+ T cells, while CD8+ T cells were more frequently directed against LT. Stimulation with JCV-specific VP1 and LT peptides indicated only low-level cross-recognition. The data suggest that control of BKV replication is correlated with differentiated expansion of BKV-specific cellular immune responses. [source] Limb-girdle muscular dystrophy type 2D gene therapy restores ,-sarcoglycan and associated proteins,,ANNALS OF NEUROLOGY, Issue 3 2009Jerry R. Mendell MD Objective ,-Sarcoglycan deficiency results in a severe form of muscular dystrophy (limb-girdle muscular dystrophy type 2D [LGMD2D]) without treatment. Gene replacement represents a strategy for correcting the underlying defect. Questions related to this approach were addressed in this clinical trial, particularly the need for immunotherapy and persistence of gene expression. Methods A double-blind, randomized controlled trial using rAAV1.tMCK.hSGCA injected into the extensor digitorum brevis muscle was conducted. Control sides received saline. A 3-day course of methylprednisolone accompanied gene transfer without further immune suppression. Results No adverse events were encountered. SGCA gene expression increased 4,5-fold over control sides when examined at 6 weeks (2 subjects) and 3 months (1 subject). The full sarcoglycan complex was restored in all subjects, and muscle fiber size was increased in the 3-month subject. Adeno-associated virus serotype 1 (AAV1)-neutralizing antibodies were seen as early as 2 weeks. Neither CD4+ nor CD8+ cells were increased over contralateral sides. Scattered foci of inflammation could be found, but showed features of programmed cell death. Enzyme-linked immunospot (ELISpot) showed no interferon-, response to ,-SG or AAV1 capsid peptide pools, with the exception of a minimal capsid response in 1 subject. Restimulation to detect low-frequency capsid-specific T cells by ELISpot assays was negative. Results of the first 3 subjects successfully achieved study aims, precluding the need for additional enrollment. Interpretation The finding of this gene replacement study in LGMD2D has important implications for muscular dystrophy. Sustained gene expression was seen, but studies over longer time periods without immunotherapy will be required for design of vascular delivery gene therapy trials. Ann Neurol 2009;66:290,297 [source] | |||||||||||||