Search results for "HLA-A2"
showing 10 items of 60 documents
Quantification of CD8+ T lymphocytes responsive to human immunodeficiency virus (HIV) peptide antigens in HIV-infected patients and seronegative pers…
1998
/ T cells responding to HIV-1 peptides were observed in none of 11 HIV- seronegative donors without a history of HIV exposure. ELISPOT assays are relatively fast and easy to perform and appear to reliably detect T cell reactivity due to previous exposure to HIV. These findings support the use of the ELISPOT assay for monitoring T cell responsiveness to HIV peptides. In acute infection with the human immunodeficiency virus We described recently an enzyme-linked immunospot (ELISPOT) assay to detect and quantitate single blood-de- type 1 (HIV-1), initial reduction in virus load is associated with the appearance of a high frequency of antiviral cytotoxic T rived CD8 / T lymphocytes forming tumo…
Impact of CMV and EBV seropositivity on CD8 T lymphocytes in an old population from West-Sicily.
2007
Abstract Herpes viruses (particularly CMV and to some extent EBV) might play a role in accelerating the deterioration of immune functions with age. Indeed, it has been demonstrated that chronic infection with CMV causes an expansion of specific CD8 T lymphocytes and that this is related to a shrinkage of the T cell repertoire in very elderly people, predicting mortality. We have analysed CD8 T cells in young and old healthy Sicilians who were both CMV- and EBV-seropositive. Our data confirm expansions of T cells specific for the HLA-A2-restricted pp65 (495–503) CMV epitope up to nearly 14% of total peripheral CD8 cells in certain elderly individuals (range 0–14%). However, the mean percenta…
Identification of a Conserved HLA-A2-Restricted Decapeptide from the IE1 Protein (pUL123) of Human Cytomegalovirus
2002
Abstract Control of human cytomegalovirus (HCMV) infection is predominantly mediated by cytolytic CD8 + T lymphocytes (CTL). Among the roughly 200 HCMV-encoded polypeptides, the tegument protein pp65 (ppUL83) and the nonstructural IE1 protein are considered to be dominant CTL targets. Yet the importance of CTL against IE1 for protective immunity against HCMV reactivation and disease has remained elusive. Analyses have been difficult, as all MHC class I presented peptides of IE1 defined so far are located in parts of the protein that are variable between viral strains. In this study a conserved decameric peptide from IE1 (P6, IE1 354–363 ) that bound to HLA-A2 was identified. Using peptide-p…
Evaluating Human T-Cell Therapy of Cytomegalovirus Organ Disease in HLA-Transgenic Mice
2015
Reactivation of human cytomegalovirus (HCMV) can cause severe disease in recipients of hematopoietic stem cell transplantation. Although preclinical research in murine models as well as clinical trials have provided 'proof of concept' for infection control by pre-emptive CD8 T-cell immunotherapy, there exists no predictive model to experimentally evaluate parameters that determine antiviral efficacy of human T cells in terms of virus control in functional organs, prevention of organ disease, and host survival benefit. We here introduce a novel mouse model for testing HCMV epitope-specific human T cells. The HCMV UL83/pp65-derived NLV-peptide was presented by transgenic HLA-A2.1 in the conte…
Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition
2009
AbstractHuman cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2–11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein stil…
Recognition of human renal cell carcinoma and melanoma by HLA-A2-restricted cytotoxic T lymphocytes is mediated by shared peptide epitopes and up-reg…
1996
Cytotoxic T lymphocytes (CTL) have previously been isolated from peripheral blood of patients with renal cell carcinoma (RCC). The CD8-positive CTL line MZ1257-CTL-5 (CTL-5) has been shown to lyse autologous cultured RCC cells in an HLA-A2 restricted fashion. Allogeneic, HLA-A2-matched RCC and melanoma cell lines were also lysed by CTL-5, suggesting that melanoma and renal cancer share antigenic determinants. The aim of the study was to determine whether RCC and melanoma share peptide epitopes that are recognized by CTL-5 in the context of HLA-A2 molecules. Peptides were acideulated from various cell lines, separated by reversed phase high performance liquid chromatography (RP-HPLC), and as…
Heterogeneity of circulating CD8 T-cells specific to islet, neo-antigen and virus in patients with type 1 diabetes mellitus
2018
Auto-reactive CD8 T-cells play an important role in the destruction of pancreatic β-cells resulting in type 1 diabetes (T1D). However, the phenotype of these auto-reactive cytolytic CD8 T-cells has not yet been extensively described. We used high-dimensional mass cytometry to phenotype autoantigen- (pre-proinsulin), neoantigen- (insulin-DRIP) and virus- (cytomegalovirus) reactive CD8 T-cells in peripheral blood mononuclear cells (PBMCs) of T1D patients. A panel of 33 monoclonal antibodies was designed to further characterise these cells at the single-cell level. HLA-A2 class I tetramers were used for the detection of antigen-specific CD8 T-cells. Using a novel Hierarchical Stochastic Neighb…
Association Between the HLA-A2 Allele and Alzheimer Disease
2006
In the elderly, the most common cause of dementia is Alzheimer disease (AD), which is responsible for the age-related progressive neurodegenerative inflammatory condition mediated by the disease. It has been seen that several genetic and environmental factors are involved in AD onset. Epidemiologic data suggest that some genetic determinants of AD might reside in those polymorphisms that regulate immune inflammatory responses, such as the major histocompatibility complex (MHC). Therefore, several MHC polymorphisms have been in the spotlight of a large number of AD association studies. A possible association of HLA-A2 allele with increased susceptibility to AD has been the subject of debate …
High frequency of functionally active Melan-a-specific T cells in a patient with progressive immunoproteasome-deficient melanoma.
2004
AbstractTumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A–specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A–specific CTLs revealed a high cytolytic activity against allogeneic Melan-A–expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of t…
Analysis of Mycobacterium tuberculosis-Specific CD8 T-Cells in Patients with Active Tuberculosis and in Individuals with Latent Infection
2009
CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-gamma and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months a…