Search results for "inducer"
showing 10 items of 178 documents
Lymphokine profile and activation pattern of two unrelated antigen- or idiotype-specific T suppressor cell clones.
1992
Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I-Ek-restricted bovine serum albumin (BSA)-specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA-specific T helper (Th) cells. The Ts cell clone 178-4 from a BALB/c mouse is I-Ed restricted and recognizes the public J558 Id on B cells. It prevents alpha(1----3)dextran B 1355S (Dex)-specific IgG antibody production and drives Dex-specific J558 idiotype-bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using di…
Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis.
2011
Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have ena…
Interferon-regulatory factor 4 is essential for the developmental program of T helper 9 cells.
2010
Summary Interferon-regulatory factor 4 (IRF4) is essential for the development of T helper 2 (Th2) and Th17 cells. Herein, we report that IRF4 is also crucial for the development and function of an interleukin-9 (IL-9)-producing CD4 + T cell subset designated Th9. IRF4-deficient CD4 + T cells failed to develop into IL-9-producing Th9 cells, and IRF4-specific siRNA inhibited IL-9 production in wild-type CD4 + T cells. Chromatin-immunoprecipitation (ChIP) analyses revealed direct IRF4 binding to the Il9 promoter in Th9 cells. In a Th9-dependent asthma model, neutralization of IL-9 substantially ameliorated asthma symptoms. The relevance of these findings is emphasized by the fact that the ind…
Mechanisms underlying lineage commitment and plasticity of human γδ T cells.
2012
Phenotypic and functional heterogeneity are the hallmarks of effector and memory T cells. Upon antigen stimulation, γδ T cells differentiate into two major types of memory T cells: central memory cells, which patrol the blood and secondary lymphoid organs, and effector memory cells, which migrate to peripheral tissues. γδ T cells display in vitro a certain degree of plasticity in their function that is reminiscent of that which is observed in conventional CD4 T cells. Similar to CD4 T cells, in which a plethora of specialized subsets affect the host response, γδ T cells may readily and rapidly assume distinct Th1-, Th2-, Th17-, T(FH) and T regulatory-like effector functions, suggesting that…
IL-9 IN PsA
2016
Objective. To investigate the expression and tis- sue distribution of Th9-related cytokines in patients with psoriatic arthritis (PsA). Methods. Quantitative gene expression analysis of Th1, Th17, and Th9 cytokines was performed in intestinal biopsy samples obtained from patients with PsA, HLA2B272positive patients with ankylosing spondylitis (AS), patients with Crohn’s disease (CD), and healthy controls. Expression and tissue distribu- tion of interleukin-23 (IL-23), IL-17, IL-22, IL-9, and IL-9 receptor (IL-9R) were evaluated by immunohisto- chemistry and confocal microscopy. Flow cytometry was used to study the frequency of Th9 cells among periph- eral blood, lamina propria, and synovial…
Lipoprotein-induced phenoloxidase-activity in tarantula hemocyanin.
2015
Phenoloxidases play vital roles in invertebrate innate immune reactions, wound closure and sclerotization processes in arthropods. In chelicerates, where phenoloxidases are lacking, phenoloxidase-activity can be induced in the oxygen carrier hemocyanin in vitro by proteolytic cleavage, incubation with the artificial inducer SDS, or lipids. The role of protein-protein interaction has up to now received little attention. This is remarkable, as lipoproteins - complexes of proteins and lipids - are present at high concentrations in arthropod hemolymph. We characterized the three lipoproteins present in tarantula hemolymph, two high-density lipoproteins and one very high-density lipoprotein, and…
Human CD25+ regulatory T cells: two subsets defined by the integrins alpha 4 beta 7 or alpha 4 beta 1 confer distinct suppressive properties upon CD4…
2004
Down-regulation of autoreactive T cell responses in vivo includes cell-contact-dependent as well as contact-independent mechanisms. Infectious tolerance is a contact-dependent mechanism used by naturally occurring CD25(+) T regulatory cells (Tregs) to confer suppressive activity upon conventional CD4(+) T cells thereby generating secondary T helper suppressor cells(Th(sup)), which inhibit T cell activation via soluble mediators. Here, we describe two distinct subsets of human Tregs, characterized by expression of either the alpha(4)beta(7) integrin or the alpha(4)beta(1) integrin. Upon activation, both subsets show an enhanced expression of FoxP3, recently described as a key transcription f…
Immunological and biological identification of tumour necrosis-like factor in sponges: Endotoxin that mediates necrosis formation in xenografts
1992
Xenografts of the sponge Geodia cydonium in its closely related species G. rovinjensis resulted in a rapid rejection of the graft within a period of 5 days. We identified an immunoreactive tumour necrosis factor (TNF)-like activity in the xenograft (Mr of 30,000) two days after grafting. In-vivo injection of 5 micrograms human recombinant TNF-alpha induced cytotoxicity in sponge cells in the same pattern and time course as during natural xenograft rejection. Anti-TNF-alpha polyclonals were found to react with xenograft extracts, by Western blot analysis, as from day 2 after grafting. Using ELISA we detected the TNF-like activity from day 2 after grafting with peak levels at days 4 and 5, wh…
Analysis of impaired in vitro immunoglobulin synthesis in rheumatoid arthritis.
1990
Decreased immunoglobulin production in pokeweed mitogen driven lymphocyte cultures has been reported in rheumatoid arthritis (RA). Here various activators and experimental designs have been used to determine the contribution of B cells, T cells, or monocytes to this low response. Sixty patients with RA and paired controls were studied at the onset of disease and again six months later. Concentrations of IgA, IgG, and IgM in cultures of RA peripheral blood mononuclear cells stimulated with thymus dependent activators were already decreased at the onset of the disease. Six months later RA mononuclear cells produced even lower concentrations of immunoglobulin. In contrast, stimulation with a T…
Cloned T helper cells reverting to a resting state develop increasing sensitivity in their antigen-mediated interaction with accessory cells.
1988
A cloned murine T cell line, KIII5, specific for the polypeptide poly-L(Tyr,Glu)-poly-D,L-Ala--poly-L-Lys [(T,G)-A--L] was compared at different stages after antigenic stimulation with respect to the conditions required for the reinduction of growth by varying concentrations of antigen presented on different types of accessory cells (AC). We show that the dose of antigen necessary for inducing half maximal proliferation in the presence of splenic AC shifts to considerably lower concentrations when the T cell blasts revert to a resting state (100 micrograms/ml on day 7 to 10 micrograms/ml on day 21-35). During the same time period the expression of interleukin 2 (IL2) receptor and the reacti…