Search results for "Lymphocyte Activation"
showing 10 items of 414 documents
The human hepatic asialoglycoprotein receptor is a target antigen for liver-infiltrating T cells in autoimmune chronic active hepatitis and primary b…
1990
Autoantibodies to the human hepatic asialoglycoprotein receptor have been found in nearly 50% of the sera of patients with autoimmune chronic active hepatitis and in 15% of patients with primary biliary cirrhosis. In this study we demonstrate that the human hepatic asialoglycoprotein receptor is also a target antigen for T cell-mediated immune responses. Peripheral blood lymphocytes of 37% (7 of 19) of patients with autoimmune chronic active hepatitis and 33% (2 of 6) of patients with primary biliary cirrhosis showed a proliferative response to highly purified human hepatic asialoglycoprotein receptor, whereas no proliferation was found with peripheral blood lymphocytes of patients with chr…
The cellular immune responses induced in the follow-up of interferon-α treated patients with chronic hepatitis C may determine the therapy outcome
1998
Abstract Background/Aims: To study whether the host's immune response determines viral clearance in chronic hepatitis C, virological markers and antigen-specific T cell reactions were analysed in 30 chronic HCV carriers followed up during interferon-α therapy, 11 untreated anti-HCV positive individuals and 10 healthy controls. Methods: Proliferative T helper cell responses to recombinant HCV core and non-structural antigens were monitored by 3 H-thymidine uptake assay and compared to quantitative viraemia levels and HCV genotypes. Results: Of the 30 treated patients, six had sustained complete responses (20%), another six were transient therapy responders (20%) and 18 were non-responders (6…
Oxidative stress in marathon runners: interest of antioxidant supplementation
2006
We have recently reported that xanthine oxidase is involved in the generation of free radicals in exhaustive exercise. Allopurinol, an inhibitor of xanthine oxidase, prevents it. The aim of the present work was to elucidate the role of exercise-derived reactive oxygen species in the cell signalling pathways involved in the adaptation to exercise in man. We have found that exercise causes an increase in the activity of plasma xanthine oxidase and an activation of NF-κB in peripheral blood lymphocytes after marathon running. This activation is dependent on free radical formation in exercise: treatment with allopurinol completely prevents it. In animal models, we previously showed that NF-κB a…
Predominance of Th1-type T cells in synovial fluid of patients with Yersinia-induced reactive arthritis
1992
The pathogenetic mechanisms underlying the development of reactive arthritis and the functional capacities of synovial T cells specific for Yersinia enterocolitica are still unclear. In this study we have determined the cytokine secretion patterns of 24 CD4+ synovial fluid (SF)-derived T cell clones from 2 patients with Yersinia-induced reactive arthritis, 16 clones specific for different Yersinia antigens and 8 clones as controls. The clones specific for Yersinia antigens predominantly belong to the T helper cell 1 (Th1) subset with production of interferon (IFN)-gamma and interleukin (IL)-2, but no IL-4, whereas SF T cells not reactive with Yersinia antigens produce IL-2, IL-4 and IFN-gam…
Static magnetic fields generated by a 0.5T MRI unit affects in vitro expression of activation markers and interleukin release in human peripheral blo…
2001
To investigate the effects of the static magnetic field (SMF) generated by a 0.5 T superconducting MRI unit on in vitro activation marker expression and interleukin release in human peripheral blood mononuclear cell (PBMC) samples from healthy volunteers.PBMC samples were split into two groups: exposed and sham-exposed under isothermal conditions. PBMC were exposed for 2 h at 24 degrees C to the SMF of a 0.5 T superconducting MRI unit. Immediately after exposure, both samples were cultured for 24 h at 37 degrees C with or without mitogenic stimulation by phytohaemagglutinin (PHA). PBMC were examined for expression of CD25, CD69 and CD71 by immunofluorescence analysis and supernatants were a…
Interleukin-5 production by mononuclear cells from aged individuals: implication for autoimmunity.
1999
It is well known that in the elderly a deterioration of immune functions may occur. Particularly, stimulation of T cells from aged individuals leads to different kind and/or size of responses if compared with the responses obtained from T cells from young individuals. At the same time, an increase in prevalence of autoantibodies occurs in elderly. The altered production of certain cytokines might explain this paradox of decreased responsiveness to foreign antigens in the face of an increased response to self-antigens. We and others have suggested that this kind of immune response might depend on an age-associated impairment of Th-1 type function that selectively affects production of cytoki…
Circadian variations in antigen-specific proliferation of human T lymphocytes and correlation to cortisol production.
1995
Cortisol is a well-known immunosuppressant when used therapeutically. The present investigation was set out to study if diurnal variations in endogenous cortisol production are reflected by changes in proliferative responses of human lymphocytes to either a mitogen (phytohemagglutinin-A, PHA) or an antigen (tetanus toxoid, TT) stimulus. The study included eight healthy volunteers. Blood was withdrawn at 0200, 0600, 1000, and 1800h for preparation of lymphocytes and determination of cortisol in plasma. Isolated cells were incubated without (baseline activity) or with inclusion of either 1 micrograms PHA or 10 micrograms TT. Proliferation was measured by labelling with 3H-thymidine for 16 h o…
HLA-B27-derived peptides as autoantigens for T lymphocytes in ankylosing spondylitis
1997
Objective.To study whether peptides derived from the HLA-B27 molecule sequence can stimulate peripheral blood T lymphocytes (PBL) from patients with HLA-B27-associated spondylarthropathies. Methods.PBL from 55 HLA-B27+ patients with ankylosing spondylitis (AS), 28 HLA-B27+ patients with other spondylarthropathies, 7 rheumatoid arthritis patients, and 30 HLA-B27+ and 22 HLA-B27- healthy controls were tested in lymphocyte proliferation assays with 4 synthetic peptides derived from the HLA-B*2705 molecule. Results. A 13-mer peptide (B27PA) induced significant proliferative responses in 17 of the 55 AS patients (stimulation index [SI] 2.5–17.5), as well as in 3 of the HLA-B27+ healthy controls …
Soluble Interleukin-2 Receptor Secretion Defectin Vitroin HLA-B8, DR3 Positive Subjects
1990
Several studies have shown that HLA-B8,DR3 positive subjects may display T cell dysfunctions. Recently, a soluble form of the receptor for IL-2 (sIL-2R) has been demonstrated in human sera and in vitro-stimulated culture supernatant from human T lymphocytes. In the present paper we report sIL-2R serum levels and sIL-2R production from peripheral blood mononuclear cells in HLA-B8,DR3 positive subjects. We found that HLA-B8,DR3 positive subjects have the highest values of serum sIL-2R, but comparing the values of these subjects with those of negative ones no significant difference was observed. As regards the in vitro production of sIL-2R, no difference exists for unstimulated cultures, where…
Double Negative (CD19+IgG+IgD-CD27-) B Lymphocytes: A New Insight from Telomerase in Healthy Elderly, in Centenarian Offspring, and in Alzheimer’s Di…
2014
Background: We have previously reported the increase of IgD-CD27- (Double Negative, DN) B cell population in the aged. These memory B cells have short telomeres and poor abilities to proliferate in vitro. Here, we investigated whether the low ability of DN B cells to proliferate depends on the expression levels of the CD307d and CD22 inhibitory receptors or whether DN B cells can proliferate and reactivate telomerase by the engagement of both innate and adaptive immune receptors. Methods: Phenotypic analyses were made by using flow cytometry. Quantitative analysis of telomerase activity was made by using a TRAP and a photometric enzyme immunoassay in young, healthy elderly, centenarian offs…