Search results for "T Cell"
showing 10 items of 2228 documents
Induction of Interleukin 10–Producing, Nonproliferating Cd4+ T Cells with Regulatory Properties by Repetitive Stimulation with Allogeneic Immature Hu…
2000
The functional properties of dendritic cells (DCs) are strictly dependent on their maturational state. To analyze the influence of the maturational state of DCs on priming and differentiation of T cells, immature CD83− and mature CD83+ human DCs were used for stimulation of naive, allogeneic CD4+ T cells. Repetitive stimulation with mature DCs resulted in a strong expansion of alloreactive T cells and the exclusive development of T helper type 1 (Th1) cells. In contrast, after repetitive stimulation with immature DCs the alloreactive T cells showed an irreversibly inhibited proliferation that could not be restored by restimulation with mature DCs or peripheral blood mononuclear cells, or by…
Tcgfiii/p40 is produced by naive murine cd4+ t cells but is not a general t cell growth factor*
1989
Several antigen-specific T cell lines were found to secrete a lymphokine upon activation by antigen or lectin that was provisionally termed T cell growth factor III (TCGF III) because it induced the proliferation of a CD4+ T cell clone independently from IL2 and IL4. Amino acid sequence analysis (and the functional properties of TCGF III) revealed that TCGF III was identical with a recently identified lymphokine termed P40. TCGF III/P40 was not only produced by long-term cultured T cell lines but also upon stimulation of freshly isolated Mlsa-reactive T cells. In addition, naive CD4+ T cells secreted TCGF III/P40 upon activation by lectin or allo-major histocompatibility complex structures.…
Autocrine transforming growth factor- from chronic lymphocytic leukemia-β cells interferes with proliferative T cell signals
1999
Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of noncycling B cells in lymphatic and extralymphatic tissues. In the present study we investigated the possible contribution of TGF-beta, as secreted by CLL-B cells, on this low proliferative state. CLL-B cells were shown to express TGF-beta RNA and to release bioactive TGF-beta into culture supernatants. Antibody neutralization of endogenously secreted TGF-beta increased the proliferation of CLL-B cells as cultured in the presence of IL-2 or IL-4 or in direct contact with activated CD4+ T cells. In these culture systems, addition of exogenous TGF-beta downregulated basal and cytokineinduced proliferation of CLL-B cell…
Highly focused T cell responses in latent human pulmonary Mycobacterium tuberculosis infection.
2005
Abstract The elucidation of the molecular and immunological mechanisms mediating maintenance of latency in human tuberculosis aids to develop more effective vaccines and to define biologically meaningful markers for immune protection. We analyzed granuloma-associated lymphocytes (GALs) from human lung biopsies of five patients with latent Mycobacterium tuberculosis (MTB) infection. MTB CD4+ and CD8+ T cell response was highly focused in the lung, distinct from PBL, as assessed by TCR-CDR3 spectratyping coupled with a quantitative analysis of TCR VB frequencies. GALs produced IFN-γ in response to autologous macrophages infected with MTB and to defined MTB-derived HLA-A2-presented peptides Ag…
Increased antigen presentation efficiency by coupling antigens to MHC class I trafficking signals.
2007
Abstract Genetic modification of vaccines by linking the Ag to lysosomal or endosomal targeting signals has been used to route Ags into MHC class II processing compartments for improvement of CD4+ T cell responses. We report in this study that combining an N-terminal leader peptide with an MHC class I trafficking signal (MITD) attached to the C terminus of the Ag strongly improves the presentation of MHC class I and class II epitopes in human and murine dendritic cells (DCs). Such chimeric fusion proteins display a maturation state-dependent subcellular distribution pattern in immature and mature DCs, mimicking the dynamic trafficking properties of MHC molecules. T cell response analysis in…
Mutant MHC class II epitopes drive therapeutic immune responses to cancer
2015
Tumour-specific mutations are ideal targets for cancer immunotherapy as they lack expression in healthy tissues and can potentially be recognized as neo-antigens by the mature T-cell repertoire. Their systematic targeting by vaccine approaches, however, has been hampered by the fact that every patient's tumour possesses a unique set of mutations ('the mutanome') that must first be identified. Recently, we proposed a personalized immunotherapy approach to target the full spectrum of a patient's individual tumour-specific mutations. Here we show in three independent murine tumour models that a considerable fraction of non-synonymous cancer mutations is immunogenic and that, unexpectedly, the …
Dendritic Cells Lose Ability to Present Protein Antigen after Stimulating Antigen-Specific T Cell Responses, despite Upregulation of MHC Class II Exp…
2000
Abstract Immature dendritic cells (DC) take up, process and present protein antigens; mature DC are specialized for stimulating primary T cell responses with increased expression of MHC class II and co-stimulatory molecules, but are incapable of processing and presenting soluble protein. The current study examined whether maturation of DC is triggered by T cell recognition of antigens presented by immature DC. Human DC derived from CD34+ progenitor cells by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) in serum-free medium could prime naive CD4+ T cells to keyhole limpet hemocyanin (KLH) and ovalbumin (OVA). The cultured DC retained the abil…
Selection of distinct Valpha/beta T-cell receptor families during in vivo and in vitro T-cell maturation.
1999
The experimental conditions influencing the use of Valphabeta TCR families were examined in lymph node (LN) cells from peptide-immunized C57BL/6 and Vbeta8.2 transgenic mice. Expanded proportions of Vbeta5, Vbeta8.2, Vbeta9, Vbeta12 and Vbeta14 positive cells and an association of Vbeta8.2 with Valpha11 was found in freshly harvested 8-day or 34-day immune LN cells. In contrast, peptide-specific T-cell lines generated in vitro from 8-day immune lymph node cells were found to be almost exclusively of the Valpha2/Vbeta12 family. However, T-cell lines originating from Vbeta8.2 transgenic mice did not show preferential Valpha usage. Anti-Vbeta8.2 antibody produced different effects: when added …
Human CD4+CD25+ regulatory T cells and infectious tolerance.
2004
Control of autoaggressive T cells by regulatory T cells (Treg) is essential to ensuring peripheral tolerance. Several subsets of CD(4+) T cells with suppressive properties have been described, including induced T helper (Th) type 3 and T regulatory (Tr) type 1 cells and naturally occurring CD(4+)CD(25+) Treg. CD(4+)CD(25+) Treg suppress the response of conventional T cells in a cell contact-dependent manner, whereas Th3 and Tr1 cells produce immunosuppressive cytokines. Two subsets of human CD(4+)CD(25+) Treg, characterized by expression of the integrins alpha4beta7 or alpha4beta1, are able to convey suppressive capacity to conventional CD(4+) T cells, thereby generating Th suppressor cells…
Effect of female genital schistosomiasis and anti-schistosomal treatment on monocytes, CD4+ T-cells and CCR5 expression in the female genital tract
2014
Published version of an article from the journal: PLoS One. Also available from the publisher: http://dx.doi.org/10.1371/journal.pone.0098593 BACKGROUND: Schistosoma haematobium is a waterborne parasite that may cause female genital schistosomiasis (FGS), characterized by genital mucosal lesions. There is clinical and epidemiological evidence for a relationship between FGS and HIV. We investigated the impact of FGS on HIV target cell density and expression of the HIV co-receptor CCR5 in blood and cervical cytobrush samples. Furthermore we evaluated the effect of anti-schistosomal treatment on these cell populations. DESIGN: The study followed a case-control design with post treatment follow…