The aim of this study was to verify the correlation of self-reported sleep and awake bruxism with demographic characteristics, oral behaviors, anxiety, temporomandibular disorder (TMD) signs and symptoms, sleep quality, and orthodontic treatment history in dental students. A total of 104 students of Dentistry located in Paraná (South Brazilian State) answered the following self-administered questionnaires: Oral Behavior Checklist, State Anxiety Inventory, TMD signs and symptoms questionnaire, and the Pittsburgh Sleep Quality Index. Associations between possible awake bruxism (AB) and sleep bruxism (SB) with sleep quality, anxiety, and TMD were analyzed by Poisson Regression with robust variance.
View Article and Find Full Text PDFPurpose The study investigated whether the auditory brainstem response (ABR) at a baseline and at higher repetition rates can detect if neurodegeneration has occurred in adults living with HIV who present with normal behavioral pure-tone thresholds. Method An exploratory research design was used. Forty adults with HIV (80 ears, 57.
View Article and Find Full Text PDFMyelin basic protein (MBP)-specific T cells are thought to play a role in the development of multiple sclerosis. MBP residues 111-129 compose an immunodominant epitope cluster restricted by HLA-DRB1*0401. The sequence of residues 111-129 of MBP (MBP(111-129)) differs in humans (MBP122:Arg) and mice (MBP122:Lys) at aa 122.
View Article and Find Full Text PDFH2-deleted, HLA-A2, or HLA-B7 transgenic mice were used to identify new human cytomegalovirus (HCMV)-derived major histocompatibility complex class I-restricted epitopes. Three different approaches for mice immunization were compared for their ability to induce a cytotoxic CD8(+) T cell (CTL) response: (1). inoculation of infectious HCMV, (2).
View Article and Find Full Text PDFObjective: It is not yet known whether the absence of certain T cell receptor V(beta) (TCRBV) genes (e.g., due to genomic deletion) has functional significance.
View Article and Find Full Text PDFCD8(+) T cells play a central role in immune protection against infection with Mycobacterium tuberculosis. One of the target epitopes for anti-M. tuberculosis directed CD8(+) T cells is the HLA-A2-restricted 19-kDa lipoprotein peptide VLTDGNPPEV.
View Article and Find Full Text PDFHuman cytomegalovirus (HCMV) and adenovirus cause significant morbidity and mortality in immunocompromised hosts undergoing allogeneic stem cell transplantation. We have previously established a procedure for the generation of polyclonal CTL with specificity against adenovirus and HCMV using a recombinant adenovirus encoding the HCMV pp65 protein (RAdpp65). However, specific CTL expanded after in vitro culture steps were subjected to several in vitro restimulations and, depending on the protocol adopted, this could lead to a selection bias, compromising the clinical benefit.
View Article and Find Full Text PDFModifications in tumour antigen-derived epitopes that stabilize the major histocompatibility complex (MHC)-peptide complex result in enhanced stimulatory capacity and improved immunogenicity of the altered peptide. These epitope analogues are attractive candidates for the development of peptide-based vaccine trials. Any modification, however, in tumour antigens may induce T-cell responses that could either fail to react against the naturally occurring peptides or represent only a subset of the total antigen-specific repertoire.
View Article and Find Full Text PDFRecent studies have suggested that vaccination induces alterations in the T cell receptor (TCR) repertoire. We investigate the diversity of the TCR repertoire after immunization with a recombinant hepatitis B surface vaccine in seven healthy subjects in CD8+ T cells in peripheral blood lymphocytes. Cellular immune responses were monitored over time by sorting CD8 T cells followed by TCR-VA and -VB complementarity determining region 3 (CDR3) analysis.
View Article and Find Full Text PDFMonitoring of CD8+ T-cell responses in cancer patients during peptide vaccination is essential to provide useful surrogate markers and to demonstrate vaccine efficacy. We have longitudinally followed CD8+ T-cell responses in 3 melanoma patients who were immunized with peptides derived from Melan-A/MART-1. Recombinant HLA-A2 tetramers loaded with the naturally presented Melan-A/MART-1 nonamer peptide (AAGIGILTV) and the Melan-A/MART-1 analog (ELAGIGILTV) were used in combination with phenotypical analysis for different T-cell subsets including naive T cells, effector T cells, "true memory" T cells and "memory effector" T cells, based on CD45RA/RO and CCR7-expression.
View Article and Find Full Text PDFSoluble MHC class I molecules loaded with antigenic peptides are available either to detect and to enumerate or, alternatively, to sort and expand MHC class I-restricted and peptide-reactive T cells. A defined number of MHC class I/peptide complexes can now be implemented to measure T cell responses induced upon Ag-specific stimulation, including CD3/CD8/zeta-chain down-regulation, pattern, and quantity of cytokine secretion. As a paradigm, we analyzed the reactivity of a Melan-A/MART-1-specific and HLA-A2-restricted CD8(+) T cell clone to either soluble or solid-phase presented peptides, including the naturally processed and presented Melan-A/MART-1 peptide AAGIGILTV or the peptide analog ELAGIGILTV presented either by the HLA-A2 wild-type (wt) or mutant (alanineright arrowvaline aa 245) MHC class I molecule, which reduces engagement of the CD8 molecule with the HLA-A2 heavy chain.
View Article and Find Full Text PDFAntigen-specific T-cell responses may be described by combining three categories: (i) the specificity and effector functions of a T-cell population, (ii) the quantity of T-cell responses (i.e., the number of responding T cells within the CD4/CD8 population), and (iii) the "quality" of T cells (defined by the T-cell receptor [TCR] structure).
View Article and Find Full Text PDFMHC class I tetramers containing peptide epitopes are sensitive tools for detecting antigen-specific CD8(+) T-cell responses. We demonstrate here that binding of HLA-A2 tetramers to CD8(+) T cells specific for the melanoma-associated antigen Melan-A/MART-1 can be fine-tuned by altering either the bound peptide epitope or residues in the alpha 3 domain of HLA-A2, which is important for CD8 binding. Antigen-specific T cells expressing high levels of CD8 could be detected using HLA-A2 tetramers containing the peptide AAGIGILTV, an epitope which is naturally processed and presented from Melan-A/MART-1.
View Article and Find Full Text PDFAlthough there has been extensive analysis on the capacity of MHC-peptide tetramers to bind antigen-specific TCR, there have been comparatively few studies regarding the role of the CD4 and CD8 co-receptors in binding and activation by these multimeric molecules. Here, we start from the observation that different antibodies against human CD8 exert opposite effects on MHC-peptide tetramer binding to the TCR: tetramer staining was enhanced by OKT8 antibody, while it was blocked with SK1 antibody. We used these different anti-CD8 antibodies to modulate CD8 function during tetramer staining of Melan-A/MART1-specific CTL clones.
View Article and Find Full Text PDFCD8+ T cells can be grouped into two different types of secretory T lymphocytes, based on the cytokine-secretion pattern upon antigen exposure: those with a T-cell cytotoxic type 1 response (Tc1), which secrete interferon-gamma (IFN-gamma), or those with a T-cell cytotoxic type 2 response, which secrete interleukin (IL)-4 and IL-10. We examined the CD8+ T-cell response directed against an immunodominant human leucocyte antigen (HLA)-A2-presented peptide derived from a 19-kDa Mycobacterium tuberculosis-associated antigen. T cells were examined by functional analysis and by T-cell receptor (TCR) complementarity-determining region 3 (CDR3)-spectratyping, which defines the complexity of a T-cell response.
View Article and Find Full Text PDFRNA viruses undergo rapid sequence variation as the result of error-prone RNA replication mechanisms. When viable mutations arise in RNA regions encoding B or T cell epitopes, mutant viruses that can evade immune detection may be selected. In the carefully studied CTL response to the Gag p11C(C-M) epitope in SIVmac-infected Mamu-A*01(+) rhesus monkeys, it has been shown that CTL recognition of that epitope can occur even in the face of accruing mutations.
View Article and Find Full Text PDFVitiligo is a common skin disease characterized by the presence of well circumscribed, depigmented, milky white macules devoid of identifiable melanocytes. Although the detection of circulating anti-melanocytic antibodies and of infiltrating lymphocytes at the margin of lesions supports the view that vitiligo is an autoimmune disorder, its etiology remains unknown. In particular, it is still a matter of debate whether the primary pathogenic role is exerted by humoral or cellular abnormal immune responses.
View Article and Find Full Text PDFWhile tumor-associated antigen (TAA)-specific CD8(+) T lymphocytes have been detected in metastatic melanoma patients, immune response in early disease phases has not yet been carefully evaluated. We looked for circulating cytotoxic T lymphocytes (CTL) directed against Melan-A / MART1, tyrosinase, gp100 and MAGE-3 antigens in patients with a diagnosis of primary cutaneous melanoma by using fluorescent HLA-A2 tetramers. In five out of six cases high numbers of CD8(+)/tetramer(+) cells could be detected by flow cytometry, and in four patients lymphocyte populations specific for two different melanoma antigens (Melan-A/MART1 and tyrosinase) were contemporaneously present.
View Article and Find Full Text PDFBackground: Th2 cells govern allergic disorders. Mechanisms leading to the Th2 commitment are dominated by the requirement of IL-4. A potential source of this triggering IL-4 could be the CD4 + subset of a small population of T cells, natural T (NT) cells.
View Article and Find Full Text PDFOligoclonal expansion of antigen-specific T cells occurs frequently during inflammatory diseases. These cells may persist for a long time at high frequency in the body and be enriched in the affected tissues. As a screening test for expanded cell T cell populations at sites of inflammation, we developed an optimized methodology for flow-cytometry-based quantification of T cell receptor Vbeta (TCRBV) expression.
View Article and Find Full Text PDFCD8(+) T cells are thought to play an important role in protective immunity to tuberculosis. Although several nonprotein ligands have been identified for CD1-restricted CD8(+) CTLs, epitopes for classical MHC class I-restricted CD8(+) T cells, which most likely represent a majority among CD8(+) T cells, have remained ill defined. HLA-A*0201 is one of the most prevalent class I alleles, with a frequency of over 30% in most populations.
View Article and Find Full Text PDFSeveral characteristics make human papillomavirus (HPV) amenable to vaccination. Anti-HPV-directed vaccines are based on the observation that HPV E6 and E7 oncoproteins are constitutively expressed in HPV-positive cervical cancer and may serve as tumor rejection antigens. Five HPV types (16, 18, 31, 33, and 45) account for 80% of cervical cancer.
View Article and Find Full Text PDFPeptides derived from human tumor antigens have been used in a number of clinical trials to induce specific immune responses against autologous tumors in cancer patients. Although favorable clinical results were observed in single patients, immune responses correlating with tumor regression were either not detected or in case of responses, the T-cell specificity was difficult to demonstrate. In this study, we analyzed antigen-specific T-cell responses induced in the skin and in peripheral blood lymphocytes (PBL) in an HLA-A2-positive melanoma patient.
View Article and Find Full Text PDFThirty T cell receptor (TCR)gammadelta+ T cell acute lymphoblastic leukemias (T-ALL) were analyzed for their immunophenotype, as well as for the rearrangements and junctional regions of the TCRG and TCRD genes. In 15 cases membrane expression of TCRgammadelta proteins could be studied extensively by flow cytometry with a new Vgamma/Vdelta antibody panel. Virtually all TCRgammadelta+ T-ALLs expressed TdT, CD2, CD3, CD5, CD6, and CD7, but they were heterogeneous in their CD1/CD4/CD8 immunophenotype.
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