Search results for "GAMMA-DELTA"
showing 10 items of 92 documents
Gamma-delta T-cell lymphomas.
2009
Peripheral T-cell lymphomas (TCLs) are uncommon neoplasms, accounting for about 12% of all lymphoid tumors worldwide. TCLs in which gammadelta T-cell receptors are expressed (gammadelta TCLs) are extremely aggressive and rare (<1% of lymphoid neoplasms). gammadelta TCLs originate from gammadelta T cells, a small subset of peripheral T cells with direct antigen recognition capability acting at the interface between innate and adaptive immunity. Two distinct gammadelta TCL entities are recognized: hepatosplenic T-cell lymphoma (HSTL) and primary cutaneous gammadelta T-cell lymphoma (PCGD-TCL). HSTL is a well-characterized extranodal lymphoma that has a disguised onset, secondary to intrasinus…
γδT cells elicited by CMV reactivation after allo-SCT cross-recognize CMV and leukemia.
2013
Human cytomegalovirus (CMV) infections and relapse of disease remain major problems after allogeneic stem cell transplantation (allo-SCT), in particular in combination with CMV-negative donors or cordblood transplantations. Recent data suggest a paradoxical association between CMV reactivation after allo-SCT and reduced leukemic relapse. Given the potential of Vδ2-negative γδT cells to recognize CMV-infected cells and tumor cells, the molecular biology of distinct γδT-cell subsets expanding during CMV reactivation after allo-SCT was investigated. Vδ2(neg) γδT-cell expansions after CMV reactivation were observed not only with conventional but also cordblood donors. Expanded γδT cells were ca…
Are human Vδ2(pos) T cells really resistant to aging and Human Cytomegalovirus infection?()
2019
In their recent paper, Weili Xu et al. [1] described the different behaviors of Vδ1pos and Vδ2pos T cell subsets in response to lifelong stress and claimed that Vδ2pos T cells are not affected by aging and Human Cytomegalovirus (HCMV) infection. While we agree that these two γδ T cell subsets diverge both in phenotype/function and in tissue distribution, we are somewhat surprised that authors did not take into account the several previously published and contradictory experimental evidence in regards to senescence of Vδ2pos T cells [2,3]. These latter studies reported that HCMV infection not only induces a clonal expansion of a distinct Vγ9neg/Vδ2pos T cell subset, but also determines a con…
The immunogenicity of human and murine cytomegaloviruses.
2000
Cytomegaloviruses are strictly host-species-specific. During an aeon of co-evolution, virus and host have found an arrangement: the productive and cytopathogenic cycle of viral gene expression is held in check by the host's immune response. As a consequence, cytomegalovirus disease is restricted to the immunocompromised host. The virus has evolved strategies to avoid its elimination and eventually hides itself in a silent state, referred to as 'viral latency'. Redundant molecular mechanisms have been identified by which cytomegaloviruses interfere with antigen presentation pathways to 'evade' immune control. In the annual period covered by this review, the IE1 protein was revisited as an im…
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…
Drug-induced expansion and differentiation of Vγ9Vδ2 T cells in vivo: The role of exogenous IL-2
2005
Human Vgamma9Vdelta2 T cells recognize nonpeptidic Ags generated by the 1-deoxy-d-xylulose 5-phosphate (many eubacteria, algae, plants, and Apicomplexa) and mevalonate (eukaryotes, archaebacteria, and certain eubacteria) pathways of isoprenoid synthesis. The potent Vgamma9Vdelta2 T cell reactivity 1) against certain cancer cells or 2) induced by infectious agents indicates that therapeutic augmentations of Vgamma9Vdelta2 T cell activities may be clinically beneficial. The functional characteristics of Vgamma9Vdelta2 T cells from Macaca fascicularis (cynomolgus monkey) are very similar to those from Homo sapiens. We have found that the i.v. administration of nitrogen-containing bisphosphonat…
Targeting human {gamma}delta} T cells with zoledronate and interleukin-2 for immunotherapy of hormone-refractory prostate cancer.
2007
Abstract The increasing evidence that γδ T cells have potent antitumor activity suggests their value in immunotherapy, particularly in areas of unmet need such as metastatic carcinoma. To this end, we initiated a phase I clinical trial in metastatic hormone-refractory prostate cancer to examine the feasibility and consequences of using the γδ T-cell agonist zoledronate, either alone or in combination with low-dose interleukin 2 (IL-2), to activate peripheral blood γδ cells. Nine patients were enlisted to each arm. Neither treatment showed appreciable toxicity. Most patients were treated with zoledronate + IL-2, but conversely only two treated with zoledronate displayed a significant long-te…
Optimizing tumor-reactive γδ T cells for antibody-based cancer immunotherapy.
2010
Monoclonal antibodies (mAbs) constitute the most rapidly growing class of human therapeutics and the second largest class of drugs after vaccines. The treatment of B-cell malignancies and HER2/Neu(+) breast cancer has benefited considerably from the use of therapeutic mAbs, either alone or in combination with standard chemotherapy. Frequent relapses, however, demonstrate that the bioactivity of these mAbs is still suboptimal. The concept of improving the anti-tumor activity of mAbs is well established and potentiating the cytotoxicity induced by anticancer mAbs can be achieved by strategies that target the downstream cytolytic effector cells. The recruitment of Fcγ receptor-dependent functi…
Three cell subsets are required for the transfer of delayed-type hypersensitivity reaction by antigen-specific T cell lines.
1997
Antigen (trinitrochlorobenzene)-specific T cell lines were obtained by repeated stimulation of lymph node cells from immune mice with antigen in vitro. These T cell lines, consisting of more than 90% CD4+ Vbeta8.2+ and 6 to 9% gammadelta+ T lymphocytes, transfer contact sensitivity (CS) locally when injected at the same site as the challenge antigen, but fail to mediate a systemic passive transfer when injected i.v. Injection of T cell lines together with spleen cells from mice immunized 1 day beforehand (1-day cells) allowed a successful, specific systemic transfer of CS. Phenotypic analysis showed that the 1-day immune cell was alphabeta+, gammadelta-, sIg-, CD3+, CD4-, CD8-, CD5+, B220 (…
Ligand‐Specific αβ and γδ T Cell Responses in Childhood Tuberculosis
2000
The alphabeta and gammadelta T cell responses were analyzed in the peripheral blood of children affected by active tuberculosis (TB) and in healthy children who tested positive (PPD+) or negative (PPD-) for purified protein derivative. PPD+ healthy and diseased children responded equally well to PPD in vitro. In contrast, only 18% of PPD+ TB patients responded to peptide p38G derived from the 38-kDa protein of Mycobacterium tuberculosis. Analysis of the whole gammadelta T cell population and of its Vgamma9/Vdelta2 subset showed similar frequencies in PPD+ children with TB and in healthy PPD+ and PPD- children. Vgamma9/Vdelta2 cells from children with TB responded to 5 different phosphoantig…