Search results for " subsets."
showing 10 items of 216 documents
Classical Flt3L-dependent dendritic cells control immunity to protein vaccine
2014
DCs are critical for initiating immunity. The current paradigm in vaccine biology is that DCs migrating from peripheral tissue and classical lymphoid-resident DCs (cDCs) cooperate in the draining LNs to initiate priming and proliferation of T cells. Here, we observe subcutaneous immunity is Fms-like tyrosine kinase 3 ligand (Flt3L) dependent. Flt3L is rapidly secreted after immunization; Flt3 deletion reduces T cell responses by 50%. Flt3L enhances global T cell and humoral immunity as well as both the numbers and antigen capture capacity of migratory DCs (migDCs) and LN-resident cDCs. Surprisingly, however, we find immunity is controlled by cDCs and actively tempered in vivo by migDCs. Del…
Reciprocal stimulation of gammadelta T cells and dendritic cells during the anti-mycobacterial immune response.
2004
Gammadelta T cells and dendritic cells (DC) are two distinct cell types of innate immunity that participate in early phases of immune response against Mycobacterium tuberculosis infection. Here we show that a close functional relationship exists between these cell populations. Using an in vitro coculture system, Vgamma1 T cells from Tcrb(-/- )mice were found to be activated by DC infected in vitro with BCG, as indicated by the elevated CD69 expression, IFN-gamma secretion and cytotoxic activity. This activation process was due to a non-cognate mechanism since it required neither cell to cell contact nor interaction between the TCR and a specific antigen, but was mediated by DC-derived IL-12…
Diminished Contact Hypersensitivity Response in IL‐4 Deficient Mice at a Late Phase of the Elicitation Reaction
1997
Contact hypersensitivity (CHS) is thought to depend on the activation of T cells of Th1 and/or Tc1 type. The role of Th2/Tc2 cells in the contact allergic reaction is not clear. The aim of this study was to analyse the functional contribution of Th2/Tc2 cells in CHS using the interleukin-4 (IL-4) deficient mouse model. Interleukin-4 deficient (IL4T) and control (wt) mice were sensitized by epicutaneous application of 2,4-dinitrofluorobenzene. The ear swelling response measured 24 h after challenge was similar in IL4T and control mice. However, from 48 h onwards, ear swelling values were significantly reduced in IL4T mice. The stimulatory capacity of freshly isolated as well as 3-day culture…
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…
The effect of cyclosporin A, FK506 and rapamycin on the murine contact sensitivity reaction
1998
We have evaluated the effects of three potent immunosuppressive agents, cyclosporin A (CsA), FK506 and rapamycin, on the murine contact sensitivity (CS) reaction to the hapten trinitrochlorobenzene. Development of CS reaction requires participation of three distinct T cell subsets: alphabeta+, CD4+ T lymphocytes, which are the classical effector cell of the CS reaction, gammadelta+ T lymphocytes, and alphabeta+, double-negative (CD4- CD8-) T lymphocytes that express the B220 molecule and produce IL-4. We found that all three drugs inhibit the development of the CS reaction, but they affect different target cells. In fact, rapamycin and FK-506 block both alphabeta+, CD4+ and gammadelta+ T ly…
Association of γδ T Cells with Disease Severity and Mortality in Septic Patients
2013
ABSTRACTGamma-delta T cells are the most abundant of all epithelial-resident lymphocytes and are considered a first line of defense against pathogens in the mucosa. Our objective was to confirm the reduction in γδ T cell subsets and its relationship with mortality in patients with sepsis. We studied 135 patients with sepsis attended in the emergency department and intensive care unit of two hospitals and compared them with a similar control group of healthy subjects. The αβ and γδ T cell subsets were determined via flow cytometry according to the stage of the sepsis and its relationship with mortality. All the lymphocyte subsets were reduced with respect to the corresponding subsets in the …
Blockade of MIF-CD74 Signalling on Macrophages and Dendritic Cells Restores the Antitumour Immune Response Against Metastatic Melanoma.
2018
Mounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. While immunotherapies have shown a remarkable success in melanoma treatment, patients develop resistance by mechanisms that include the establishment of an immune suppressive tumor microenvironment. Thus, understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that macrophages (MOs) and dendritic cells (DCs) are suppressed in metastatic melanoma and that the Ig-CDR-based peptide C36L1 is able to restore MOs and …
T Helper Cell Subsets in the Pleural Fluid of Tuberculous Patients Differentiate Patients With Non-Tuberculous Pleural Effusions
2021
BackgroundTuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis (Tb). Patients with TPE or malignant pleural effusions (MPE) frequently have a similar lymphocytic pleural fluid profile. Since the etiology of PE in various diseases is different, identifying the cellular components may provide diagnostic clues for understanding the pathogenesis.ObjectiveWe determined the frequency of T helper (Th) subtypes in the PEs for differentiation of Tb and non-Tb patients.MethodsThirty patients with TPE, 30 patients with MPE, 14 patients with empyema (EMP), and 14 patients with parapneumonic effusion (PPE) were enrolled between December 2018 and December 2019…
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…