Search results for "Immunologic Memory"
showing 8 items of 88 documents
Suppressive effects of C3b on monocyte-dependent T cell proliferation.
1987
The effect of C3b treatment of human monocytes on secondary antigen-dependent T cell response was studied. When antigen-specific T cell blasts were cultivated together with C3b-treated monocytes the proliferative response was inhibited in a dose-dependent fashion. This suppressive effect was specific for C3b because heat-inactivated C3b or buffer alone had no influence on T cell proliferation. In part, this suppressive effect is mediated through a C3b-induced decreased expression of class II antigens on the surface of treated monocytes, but another suppressive mechanism exists because the C3b pretreatment of monocytes also led to an inhibition of the proliferative response in a class II ant…
Editorial: Activation, functions, and generation of immunological memory in γδ T lymphocytes: lessons from nonhuman primates
2014
T cells constitute an unconventional lymphocyte population with distinct functions complementary to those of CD4 and CD8 T cells. As such, they have both adaptive features, such as expression of the TCR, and innate-like functions reminiscent of NK cells, with whom they share extensive repertoires of activating and inhibitory receptors [1, 2]. Although most antigens recognized by murine T cells remain obscure, advances have been made in identifying ligands for human T cells. The majority of circulating human T lymphocytes expresses a TCR formed by the preferentially-paired V 9 and V 2 chains (here and thereafter, called V 9V 2 T cells). Instead of binding peptides associated with molecules b…
Transcutaneous immunization with imiquimod is amplified by CD40 ligation and results in sustained cytotoxic T-lymphocyte activation and tumor protect…
1999
Transcutaneous immunization (TCI) using ligands of Toll-like receptors (TLRs) and cytotoxic T-lymphocyte (CTL) epitopes lead to the induction of potent T-cell responses. To characterize the efficacy of TCI-mediated CTL activation, we monitored the frequency and functional activity of specific CTL induced with TCI using the ovalbumin-derived epitope SIINFEKL composed in creme containing the synthetic TLR7 ligand R-837. We found that the frequency and activity decayed rapidly 10 d post-TCI. Consistently, no significant memory T-cell formation was detectable. In a prophylactic vaccination setting, TCI was protective against a lethal challenge with ovalbumin expressing EG.7 thymoma cells when t…
Single-cell RNA sequencing unveils the shared and the distinct cytotoxic hallmarks of human TCRVδ1 and TCRVδ2 γδ T lymphocytes
2019
γδ T lymphocytes represent ∼1% of human peripheral blood mononuclear cells and even more cells in most tissues of vertebrates. Although they have important anticancer functions, most current single-cell RNA sequencing (scRNA-seq) studies do not identify γδ T lymphocytes because their transcriptomes at the single-cell level are unknown. Here we show that high-resolution clustering of large scRNA-seq datasets and a combination of gene signatures allow the specific detection of human γδ T lymphocytes and identification of their T cell receptor (TCR)Vδ1 and TCRVδ2 subsets in large datasets from complex cell mixtures. In t -distributed stochastic neighbor embedding plots from blood and tumor sa…
Human Memory Th17 Cell Populations Change Into Anti-inflammatory Cells With Regulatory Capacity Upon Exposure to Active Vitamin D
2019
Autoimmune diseases are characterized by an aberrantly activated immune system, resulting in tissue damage and functional disability in patients. An important therapeutic goal is to restore the deregulated immunological balance between pro- A nd anti-inflammatory T cells. This imbalance is illustrated by elevated levels and activity of memory Th17 cell populations, such as Th17, Th1/Th17, and Th17.1 cells, in various autoimmune diseases. These cells are characterized by the chemokine receptor CCR6, RORC expression and production of IL-17A, IFNγ, and TNFα. Using rheumatoid arthritis (RA) as a model of autoimmune disease, we here demonstrate that pro-inflammatory memory CCR6+ Th cells can swi…
Non-specific Effects of Vaccines Illustrated Through the BCG Example: From Observations to Demonstrations
2018
Epidemiological studies regarding many successful vaccines suggest that vaccination may lead to a reduction in child mortality and morbidity worldwide, on a grander scale than is attributable to protection against the specific target diseases of these vaccines. These non-specific effects (NSEs) of the Bacille Calmette-Guérin (BCG) vaccine, for instance, implicate adaptive and innate immune mechanisms, with recent evidence suggesting that trained immunity might be a key instrument at play. Collectively referring to the memory-like characteristics of innate immune cells, trained immunity stems from epigenetic reprogramming that these innate immune cells undergo following exposure to a primary…
γδ T Cells Cross-Link Innate and Adaptive Immunity in Mycobacterium tuberculosis Infection
2011
Protective immunity against mycobacterial infections such asMycobacterium tuberculosisis mediated by interactions between specific T cells and activated antigen presenting cells. To date, many aspects of mycobacterial immunity have shown that innate cells could be the key elements that substantially may influence the subsequent adaptive host response. During the early phases of infection, innate lymphocyte subsets play a pivotal role in this context. Here we summarize the findings of recent investigations onγδT lymphocytes and their role in tuberculosis immunity.
Differential requirements for antigen or homeostatic cytokines for proliferation and differentiation of human Vgamma9Vdelta2 naive, memory and effect…
2005
We have compared four human subsets of Vgamma9Vdelta2 T cells, naive (T(naive), CD45RA(+)CD27(+)), central memory (T(CM), CD45RA(-)CD27(+)), effector memory (T(EM), CD45RA(-)CD27(-)) and terminally differentiated (T(EMRA), CD45RA(+)CD27(-)), for their capacity to proliferate and differentiate in response to antigen or homeostatic cytokines. Cytokine responsiveness and IL-15R expression were low in T(naive) cells and progressively increased from T(CM) to T(EM) and T(EMRA) cells. In contrast, the capacity to expand in response to antigen or cytokine stimulation showed a reciprocal pattern and was associated with resistance to cell death and Bcl-2 expression. Whereas antigen-stimulated cells a…