Search results for "Interleukin 21"
showing 10 items of 178 documents
Protective role of nuclear factor of activated T cells 2 in CD8+ long-lived memory T cells in an allergy model
2007
Background The transcriptional regulation of cytokines released and controlled by memory T cells is not well understood. Defective IFN-γ production in allergic asthma correlates in human beings with the risk of wheezing in childhood. Objective To understand the role of the transcription factor nuclear factor of activated T cells 2 (NFATc2) in memory and effector T cells in the airways in experimental allergic asthma. Methods We used murine models of allergic asthma and adoptive cell transfer of fluorescence-activated sorted cells in a disease model. Results Mice lacking NFATc2 developed an increase in airway hyperresponsiveness (AHR), remodeling, and serum IgE levels on ovalbumin sensitizat…
Production of T suppressor factor specific for the hapten picryl chloride requires both T suppressor cells and an antigen-specific, genetically restr…
1987
Summary We investigated the requirement for activation of T suppressor cells specific for the hapten picryl chloride and the release of hapten-specific T suppressor factor. Using an in vivo experimental system, we report that activation of T suppressor cells and the consequent release of T suppressor factor required two signals: one was provided by primed T suppressor cells, i.e. spleen cells from mice injected with the tolerogen picrylsulphonic acid, and the other was provided by the specific antigen in the context of H-2 gene products. Mechanisms by which the interaction between these two signals led to activation of T suppressor cells and the production of T suppressor factor, as well as…
The NK Cell Response to Mouse Cytomegalovirus Infection Affects the Level and Kinetics of the Early CD8+ T-Cell Response
2012
ABSTRACT Natural killer (NK) cells and CD8 + T cells play a prominent role in the clearance of mouse cytomegalovirus (MCMV) infection. The role of NK cells in modulating the CD8 + T-cell response to MCMV infection is still the subject of intensive research. For analyzing the impact of NK cells on mounting of a CD8 + T-cell response and the contribution of these cells to virus control during the first days postinfection (p.i.), we used C57BL/6 mice in which NK cells are specifically activated through the Ly49H receptor engaged by the MCMV-encoded ligand m157. Our results indicate that the requirement for CD8 + T cells in early MCMV control inversely correlates with the engagement of Ly49H. W…
Phenotypical and functional analysis of memory and effector human CD8 T cells specific for mycobacterial antigens
2006
Abstract Mycobacterium tuberculosis infects one-third of the global population and claims two million lives every year. Because memory CD8 T cells exhibit a high heterogeneity in terms of phenotype and functional characteristic, we investigated the frequency, phenotype, and functional properties of Ag85A epitope-specific HLA-A*0201 CD8 T cells in children affected by tuberculosis (TB) before and 4 mo after chemotherapy and healthy contact children. Using Ag85A peptide/HLA-A*0201 pentamer, we found a low frequency of blood peptide-specific CD8 T cells in tuberculous children before therapy, which consistently increased after therapy to levels detected in healthy contacts. Ex vivo analysis of…
β2Integrin deficiency yields unconventional double-negative T cells distinct from mature classical natural killer T cells in mice
2009
Expressed on leucocytes, beta(2) integrins (CD11/CD18) are specifically involved in leucocyte function. Using a CD18-deficient (CD18(-/-)) mouse model, we here report on their physiological role in lymphocyte differentiation and trafficking. CD18(-/-) mice present with a defect in the distribution of lymphocytes with highly reduced numbers of naïve B and T lymphocytes in inguinal and axillary lymph nodes. In contrast, cervical lymph nodes were fourfold enlarged harbouring unconventional T-cell receptor-alphabeta (TCR-alphabeta) and TCR-gammadelta CD3(+) CD4(-) CD8(-) (double-negative; DN) T cells that expanded in situ. Using adoptive transfer experiments, we found that these cells did not h…
gd T cells condition dendritic cells in vivo for priming pulmonary CD8 T cell responses against Mycobacterium tuberculosis
2006
gammadelta T cells and dendritic cells are quickly recruited to the lungs shortly after intranasal vaccination with BCG, but the functional in vivo interplay between these two cell populations and its role in the induction of adaptive immune responses is unclear. Using TCR-deficient mice and bone marrow chimeras, we show here that gammadelta T cells provide a non-redundant early source of IFN-gamma in vivo, which enhances IL-12 production by lung dendritic cells. The in vivo-conditioned dendritic cells, in turn, prime a more efficient lung CD8 T cell response against Mycobacterium tuberculosis. Thus, strategies exploiting gammadelta T cell function and IFN-gamma production could be valuable…
Cell Contact–Dependent Priming and Fc Interaction with CD32+ Immune Cells Contribute to the TGN1412-Triggered Cytokine Response
2014
Abstract Following inconspicuous preclinical testing, the superagonistic anti-CD28 mAb TGN1412 was applied to six study participants who all developed a devastating cytokine storm. We verified that TGN1412 treatment of fresh PBMCs induced only moderate responses, whereas restoration of tissue-like conditions by high-density preculture (HDC) allowed vigorous cytokine production. TGN1412 treatment of T cells isolated from HDC-PBMCs induced moderate cytokine responses, which upon additional anti-IgG crosslinking were significantly boosted. Moreover, coincubation of TGN1412-treated T cells with B cells expressing the intermediate affinity Fcγ receptor IIB (CD32B), or coincubation with CD32B+ tr…
The role of accessory cells in polyclonal T cell activation. I. Both induction of interleukin 2 production and of interleukin 2 responsiveness by con…
1983
Recent studies from other laboratories have shown that concanavalin A (Con A) acts at two separate steps in polyclonal T cell activation: interleukin 2 (IL2) production, and induction of responsiveness to IL2. Using a combination of techniques for the depletion of accessory cells from lymph node T cells, we have investigated which of these steps, if not both, is responsible for the known requirement for accessory cells in the Con A response. It was found that with increasing T cell purification, first the ability is lost to produce sufficient levels of endogenous IL2, whereas induction of IL2 responsiveness can still take place. Further removal of accessory cells however yields a population…
Characterization of Human γδ T Lymphocytes Infiltrating Primary Malignant Melanomas
2012
T lymphocytes are often induced naturally in melanoma patients and infiltrate tumors. Given that gamma delta T cells mediate antigen-specific killing of tumor cells, we studied the representation and the in vitro cytokine production and cytotoxic activity of tumor infiltrating gamma delta T cells from 74 patients with primary melanoma. We found that gamma delta T cells represent the major lymphocyte population infiltrating melanoma, and both V delta 1(+) and V delta 2(+) cells are involved. The majority of melanoma-infiltrating gamma delta cells showed effector memory and terminally-differentiated phenotypes and, accordingly, polyclonal gamma delta T cell lines obtained from tumor-infiltrat…
T cells in reactive arthritis
1993
T cells appear to play a major role in the development, maintenance and also resolution of reactive arthritis (ReA). Recent advances in understanding the processes involved in T cell activation now allow us to examine the peripheral blood and synovial fluid T cell responses to given "arthritogenic" microorganisms in terms of antigen specificity, epitope identification, cytokine secretion patterns, HLA restriction and the role of different T cell subsets in ReA. Peripheral blood bulk proliferation and limiting dilution studies provide evidence that the peripheral T cell response against arthritis-associated gram-negative bacteria is decreased in patients developing immunological sequelae suc…