scholarly journals Human T Lymphocytes Are Permissive for Dengue Virus Replication

2018 ◽  
Vol 92 (10) ◽  
pp. e02181-17 ◽  
Author(s):  
Guilherme F. Silveira ◽  
Pryscilla F. Wowk ◽  
Allan H. D. Cataneo ◽  
Paula F. dos Santos ◽  
Murilo Delgobo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
Dengue Virus ◽  
Cell Activation ◽  
Vaccine Development ◽  
Viral Reservoir ◽  
Induced Apoptosis

ABSTRACTDengue virus (DV) infection can cause either a self-limiting flu-like disease or a threatening hemorrhage that may evolve to shock and death. A variety of cell types, such as dendritic cells, monocytes, and B cells, can be infected by DV. However, despite the role of T lymphocytes in the control of DV replication, there remains a paucity of information on possible DV-T cell interactions during the disease course. In the present study, we have demonstrated that primary human naive CD4+and CD8+T cells are permissive for DV infection. Importantly, both T cell subtypes support viral replication and secrete viable virus particles. DV infection triggers the activation of both CD4+and CD8+T lymphocytes, but preactivation of T cells reduces the susceptibility of T cells to DV infection. Interestingly, the cytotoxicity-inducing protein granzyme A is highly secreted by human CD4+but not CD8+T cells after exposure to DVin vitro. Additionally, using annexin V and polycaspase assays, we have demonstrated that T lymphocytes, in contrast to monocytes, are resistant to DV-induced apoptosis. Strikingly, both CD4+and CD8+T cells were found to be infected with DV in acutely infected dengue patients. Together, these results show that T cells are permissive for DV infectionin vitroandin vivo, suggesting that this cell population may be a viral reservoir during the acute phase of the disease.IMPORTANCEInfection by dengue virus (DV) causes a flu-like disease that can evolve to severe hemorrhaging and death. T lymphocytes are important cells that regulate antibody secretion by B cells and trigger the death of infected cells. However, little is known about the direct interaction between DV and T lymphocytes. Here, we show that T lymphocytes from healthy donors are susceptible to infection by DV, leading to cell activation. Additionally, T cells seem to be resistant to DV-induced apoptosis, suggesting a potential role as a viral reservoir in humans. Finally, we show that both CD4+and CD8+T lymphocytes from acutely infected DV patients are infected by DV. Our results raise new questions about DV pathogenesis and vaccine development.

scholarly journals Immunomodulatory effects of different intravenous immunoglobulin preparations in chronic lymphocytic leukemia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana Colado ◽  
Esteban Enrique Elías ◽  
Valeria Judith Sarapura Martínez ◽  
Gregorio Cordini ◽  
Pablo Morande ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
T Cell Activation ◽  
Cell Activation ◽  
Lymphocytic Leukemia ◽  
Immunomodulatory Effects ◽  
Immunoglobulin Preparations

AbstractHypogammaglobulinemia is the most frequently observed immune defect in chronic lymphocytic leukemia (CLL). Although CLL patients usually have low serum levels of all isotypes (IgG, IgM and IgA), standard immunoglobulin (Ig) preparations for replacement therapy administrated to these patients contain more than 95% of IgG. Pentaglobin is an Ig preparation of intravenous application (IVIg) enriched with IgM and IgA (IVIgGMA), with the potential benefit to restore the Ig levels of all isotypes. Because IVIg preparations at high doses have well-documented anti-inflammatory and immunomodulatory effects, we aimed to evaluate the capacity of Pentaglobin and a standard IVIg preparation to affect leukemic and T cells from CLL patients. In contrast to standard IVIg, we found that IVIgGMA did not modify T cell activation and had a lower inhibitory effect on T cell proliferation. Regarding the activation of leukemic B cells through BCR, it was similarly reduced by both IVIgGMA and IVIgG. None of these IVIg preparations modified spontaneous apoptosis of T or leukemic B cells. However, the addition of IVIgGMA on in vitro cultures decreased the apoptosis of T cells induced by the BCL-2 inhibitor, venetoclax. Importantly, IVIgGMA did not impair venetoclax-induced apoptosis of leukemic B cells. Overall, our results add new data on the effects of different preparations of IVIg in CLL, and show that the IgM/IgA enriched preparation not only affects relevant mechanisms involved in CLL pathogenesis but also has a particular profile of immunomodulatory effects on T cells that deserves further investigation.

scholarly journals Immune function of the blood-brain barrier: incomplete presentation of protein (auto-)antigens by rat brain microvascular endothelium in vitro.

1990 ◽  
Vol 110 (5) ◽  
pp. 1757-1766 ◽  
Author(s):  
W Risau ◽  
B Engelhardt ◽  
H Wekerle
Keyword(s):  
T Cells ◽  
Endothelial Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
T Cell Activation ◽  
Cell Activation ◽  
Ifn Gamma

The endothelial blood-brain barrier (BBB) has a critical role in controlling lymphocyte traffic into the central nervous system (CNS), both in physiological immunosurveillance, and in its pathological aberrations. The intercellular signals that possibly could induce lymphocytes to cross the BBB include immunogenic presentation of protein (auto-)antigens by BBB endothelia to circulating T lymphocytes. This concept has raised much, though controversial, attention. We approached this problem by analyzing in vitro immunospecific interactions between clonal rat T lymphocyte lines with syngeneic, stringently purified endothelial monolayer cultures from adult brain micro-vessels. The rat brain endothelia (RBE) were established from rat brain capillaries using double collagenase digestion, density gradient fractionation and selective cytolysis of contaminating pericytes by anti-Thy 1.1 antibodies and complement. Incubation with interferon-gamma in most of the brain-derived endothelial cells induced Ia-antigens in the cytoplasm and on the cell surface in some of the cells. Before the treatment, the cells were completely Ia-negative. Pericytes were unresponsive to IFN-gamma treatment. When confronted with syngeneic T cell lines specific for protein (auto-)antigens (e.g., ovalbumin and myelin basic protein, MBP), RBE were completely unable to induce antigen-specific proliferation of syngeneic T lymphocytes irrespective of pretreatment with IFN-gamma and of cell density. RBE were inert towards the T cells, and did not suppress T cell activation induced by other "professional" antigen presenting cells (APC) such as thymus-derived dendritic cells or macrophages. IFN-gamma-treated RBE were, however, susceptible to immunospecific T cell killing. They were lysed by MBP-specific T cells in the presence of the specific antigen or Con A. Antigen dependent lysis was restricted by the appropriate (MHC) class II product. We conclude that the interaction of brain endothelial cells with encephalitogenic T lymphocytes may involve recognition of antigen in the molecular context of relevant MHC products, but that this interaction per se is insufficient to initiate the full T cell activation program.

scholarly journals CD28 interaction with B7 costimulates primary allogeneic proliferative responses and cytotoxicity mediated by small, resting T lymphocytes.

1992 ◽  
Vol 175 (2) ◽  
pp. 353-360 ◽  
Author(s):  
M Azuma ◽  
M Cayabyab ◽  
D Buck ◽  
J H Phillips ◽  
L L Lanier
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Proliferative Response ◽  
Cell Activation ◽  
B Cell Activation ◽  
Rapid Responses ◽  
Cell Clones

Engagement of the CD3/T cell antigen receptor complex on small, resting T cells is insufficient to trigger cell-mediated cytotoxicity or to induce a proliferative response. In the present study, we have used genetic transfection to demonstrate that interaction of the B7-BB1 B cell activation antigen with the CD28 T cell differentiation antigen costimulates cell-mediated cytotoxicity and proliferation initiated by either anti-CD2 or anti-CD3 monoclonal antibody (mAb). Moreover, a B7-negative Burkitt's lymphoma cell line that fails to stimulate an allogeneic mixed lymphocyte response is rendered a potent stimulator after transfection with B7. The mixed leukocyte reaction proliferative response against the B7 transfectant is inhibited by either anti-CD28 or B7 mAb. We also demonstrate that freshly isolated small, resting human T cells can mediate anti-CD3 or anti-CD2 mAb-redirected cytotoxicity against a murine Fc receptor-bearing mastocytoma transfected with human B7. These preexisting cytotoxic T lymphocytes in peripheral blood are present in both the CD4 and CD8 subsets, but are preferentially within the CD45RO+ "memory" population. While small, resting T cells apparently require costimulation by CD28/B7 interactions, this requirement is lost after T cell activation. Anti-CD3 initiates a cytotoxic response mediated by in vitro cultured T cell clones in the absence of B7 ligand. The existence of functional cytolytic T cells in the small, resting T cell population may be advantageous in facilitating rapid responses to immune challenge.

scholarly journals Voriconazole Inhibits Fungal Growth without Impairing Antigen Presentation or T-Cell Activation

2003 ◽  
Vol 47 (6) ◽  
pp. 1818-1823 ◽  
Author(s):  
Heather L. Van Epps ◽  
Marta Feldmesser ◽  
Eric G. Pamer
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Animal Models ◽  
T Cell Activation ◽  
Cell Activation ◽  
Fungal Growth ◽  
Antifungal Drugs ◽  
Isolation And Characterization

ABSTRACT Invasive aspergillosis (IA) is the most common life-threatening invasive mold infection worldwide. The principal therapy for IA is amphotericin B, despite its known toxicity and immunosuppressive side effects. Studies in animal models of IA suggest a role for T lymphocytes in the pathology of the disease, although the precise role for Aspergillus-specific T cells remains undefined. The isolation and characterization of T lymphocytes in animal models of IA are hampered by the rapid outgrowth of the fungus in cultures derived from infected organs. In the present study, we tested the abilities of the antifungal drugs caspofungin acetate and voriconazole to inhibit fungal growth in vitro as a means of maintaining cultures of T cells from Aspergillus-infected mice. We demonstrate that while both antifungal drugs are inhibitory, only voriconazole completely inhibited fungal growth, allowing long-term maintenance of T-cell cultures. In addition, voriconazole had no inhibitory effect on the activation and maturation of dendritic cells or the proliferation of T lymphocytes. Thus, voriconazole appears to be a promising agent for use in in vitro studies of Aspergillus-specific T lymphocytes in animal models of IA.

scholarly journals Characteristics of Bursal T Lymphocytes Induced by Infectious Bursal Disease Virus

2000 ◽  
Vol 74 (19) ◽  
pp. 8884-8892 ◽  
Author(s):  
In-Jeong Kim ◽  
Seung Kwon You ◽  
Hyungee Kim ◽  
Hung-Yeuh Yeh ◽  
Jagdev M. Sharma
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Dependent Manner ◽  
Bursal Disease

ABSTRACT Infectious bursal disease virus (IBDV) is an avian lymphotropic virus that causes immunosuppression. When specific-pathogen-free chickens were exposed to a pathogenic strain of IBDV (IM), the virus rapidly destroyed B cells in the bursa of Fabricius. Extensive viral replication was accompanied by an infiltration of T cells in the bursa. We studied the characteristics of intrabursal T lymphocytes in IBDV-infected chickens and examined whether T cells were involved in virus clearance. Flow cytometric analysis of single-cell suspensions of the bursal tissue revealed that T cells were first detectable at 4 days postinoculation (p.i.). At 7 days p.i., 65% of bursal cells were T cells and 7% were B cells. After virus infection, the numbers of bursal T cells expressing activation markers Ia and CD25 were significantly increased (P < 0.03). In addition, IBDV-induced bursal T cells produced elevated levels of interleukin-6-like factor and nitric oxide-inducing factor in vitro. Spleen and bursal cells of IBDV-infected chickens had upregulated gamma interferon gene expression in comparison with virus-free chickens. In IBDV-infected chickens, bursal T cells proliferated in vitro upon stimulation with purified IBDV in a dose-dependent manner (P < 0.02), whereas virus-specific T-cell expansion was not detected in the spleen. Cyclosporin A treatment, which reduced the number of circulating T cells and compromised T-cell mitogenesis, increased viral burden in the bursae of IBDV-infected chickens. The results suggest that intrabursal T cells and T-cell-mediated responses may be important in viral clearance and promoting recovery from infection.

T Cell Pathway Deficiencies in Chronic Lymphocityc Leukemia: Partial Restoration with OKT3/IL-2 Activation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4692-4692
Author(s):  
Mauro Di Ianni ◽  
Lorenzo Moretti ◽  
Beatrice Del Papa ◽  
Maria De Ioanni ◽  
Adelmo Terenzi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Activated T Cells ◽  
Mutational Status ◽  
The Impact

Abstract As Chronic Lymphocytic Leukemia (CLL) is associated with several defects in the T cell compartment, the impact of tumour burden on the autologous immune system was studied. Gene expression profiles (using Applied Biosystem Human Genome Microarray) identified 237 genes with significantly increased expression and 221 genes with significantly decreased expression (p<0.05) in CD3+ cells from CLL patients compared with healthy donors. Panther software analysis identified 34/237 upregulated genes and 26/221 downregulated genes that were involved in specific pathways, mainly cell differentiation and proliferation, survival, apoptosis, cytoskeleton formation, vesicle trafficking and T cell activation. The 26 dowregulated genes included Zap70, a member of the syk family protein tyrosine kinase, which is involved in T-cell activation. Zap-70 results were validated by mRNA quantification by RT-PCR (−1.77 fold in comparison with healthy controls) and by flow-cytometric analysis (Mean Intensity Fluorescence=33±12 vs 80±23.62 in controls, p<0.05). To test the hypothesis that activation with OKT3 /IL-2 could bypass these T cell deficiencies, activated T cells from 20 patients with CLL were tested in vitro for cytotoxicity (using the 51chromium release assay) against mutated and unmutated (according to IgVH mutational status) autologous B cells, DAUDI, K562 and P815 cell lines. After 10 days’ culture, the T cell count remained unchanged; CD8 cells expanded more than CD4; TCR spectratyping analysis indicated no differences in TCR repertoires. Activation restored the ZAP-70 mRNA (+1.67 fold). The 51chromium release cytotoxicity assay showed an index > 30% in 5/20 patients. The other 15 were partially cytotoxic against P815, K562 and Daudi. Cell line analysis in all 20 confirmed prevalently T cell-mediated cytotoxicity and poor NK/LAK activity. Cytotoxicity did not correlate with B cell mutational status. We tested the cytotoxic activity of autologous activated T cells in NOD/SCID mice co-transplanted with leukaemic B cells. Only activated T cells exerting cytotoxicity vs autologous B-cell CLL prevent CLL in human-mouse chimera, as confirmed by PCR and FACS analysis which visualised only CD3+ cells. In conclusion, in patients with CLL, activating autologous T cells with OKT3 /IL-2 bypasses, at least in part, the T cell immunological deficiencies. These in vitro and in vivo findings might serve to throw light on new mechanisms that could be exploited in immunotherapy designed to exert disease control.

scholarly journals Lenalidomide Treatment Restores In Vivo T Cell Activity in Relapsed/Refractory FL and DLBCL

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 729-729
Author(s):  
Cedric Menard ◽  
Joelle Dulong ◽  
Tien Tuan Nguyen ◽  
Nadège Bescher ◽  
Maelle Latour ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
T Cell Proliferation ◽  
Immune Synapse ◽  
Anti Cd20

Abstract The immunostimulatory properties of lenalidomide have been mostly described in vitro while in vivo studies performed in multiple myeloma or chronic lymphocytic leukemia have reported a poorly characterized T-cell activation. A better understanding of lenalidomide kinetics and mechanisms of action is mandatory to optimize its combination with other immunotherapeutic agents in particular for the treatment of non Hodgkin lymphomas. We undertook a thorough immune monitoring of patients enrolled in the French multicenter clinical trial GALEN (ClinicalTrials.gov: NCT01582776) addressing the tolerance and efficacy of the association of lenalidomide and obinutuzumab, a glycoengineered type II anti-CD20 monoclonal antibody, in relapsed/refractory B-cell lymphomas. A 1-week interval between the start of lenalidomide and the first infusion of obinutuzumab was planned, allowing an assessment of the effect of lenalidomide alone on immune-related parameters separately from the combinatorial therapy. Serial blood samples were collected in 44 patients (16 DLBCL and 28 FL) to investigate T, B, NK, and myeloid subsets. In addition, in vitro functional assays were designed to address T cell functional features (proliferation, immune synapse, activity of regulatory T cells (Treg)). In the context of the association with obinutuzumab, we first checked that CD20 expression was not affected on circulating malignant and normal B cells (p=0.43 and 0.8; respectively). Interestingly, upon 1 week of lenalidomide treatment, normal B cells, unlike malignant B cells, upregulated MHC class II (p&lt;0.001 versus 0.16; respectively) while both increased the expression of the costimulatory molecule CD86 (p=0.001 and 0.002; respectively). More importantly, the T-cell capacity to mount a functional immune synapse with malignant B cells was restored in 5/6 relapsed/refractory patients (p&lt;0.001) and we confirmed that this stood true for 6 FL patients at diagnosis (p&lt;0.001). In addition, T cell proliferation was strongly increased in vivo as measured by Ki67 staining (p&lt;0.001) but also upon TCR stimulation ex vivo (p=0.002). This immunostimulatory effect could not be ascribed to a blockade of Treg inhibitory potential by lenalidomide as effector T-cell proliferation was similarly enhanced upon in vitro Treg depletion before and after lenalidomide treatment (p=0.02). In addition, T-cell activation was associated with a reshaping of memory T-cell distribution with the central memory subset dropping in favor of effector cells (p&lt;0.001 and 0.002 respectively). This restoration of T-cell functions was paralleled by the induction of activation markers on T cells such as HLA-DR, CD137, PD-1, and Tim-3 (p&lt;0.001 for all markers). Finally, immune stimulation was not confined to T cells as NK cells also upregulated CD137 (p&lt;0.001) but not PD-1 (p=0.53) expression. We also investigated the myeloid compartment including circulating MDSC and monocytes, both being putative precursors of tumor-associated macrophages. Within 1 week of lenalidomide, patients experienced a decrease of monocytes subsets count and an upregulation of the activation marker and Fcg receptor CD64 (p=0.006). Of note, preliminary experiments showed that, at least in some cases, in vitro exposure of macrophages to lenalidomide could enhance anti-CD20-mediated phagocytosis of tumor cells. Some of these immunological parameters were transiently modulated and returned to baseline levels upon lenalidomide washout but others were restored long term in particular the immune synapse score and memory T cell counts. We herein report for the first time early in vivo T cell activation by lenalidomide in relapse FL/DLBCL through a detailed phenotypic analysis strengthened by innovative functional assays. The study of T cells heterogeneity at the transcriptomic level is underway and the correlation of these immunomodulatory properties with clinical data is also currently being addressed. Our results will help build new and more relevant lenalidomide-based immunotherapeutic approaches. (This study was supported by research grants from Celgene and Roche companies) Disclosures Menard: Celgene: Consultancy; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy. Lamy: Roche: Consultancy, Honoraria. Morschhauser: Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Servier: Consultancy; Gilead: Consultancy. Tarte: Celgene: Consultancy, Research Funding; Novimmune: Research Funding; Roche: Consultancy.

scholarly journals T cell regulation of B cell activation. T cells independently regulate the responses mediated by distinct B cell subpopulations.

1982 ◽  
Vol 155 (5) ◽  
pp. 1267-1276 ◽  
Author(s):  
Y Asano ◽  
R J Hodes
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Free Carrier ◽  
B Cell Activation ◽  
High Concentrations ◽  
Cell Subpopulations

The present studies have been carried out to characterize the regulatory influences acting upon defined pathways of T cell-dependent B cell activation. In these studies, it was demonstrated that high concentrations of free carrier strongly inhibited the MHC-restricted in vitro T cell-dependent antibody responses of primed Lyb-5- B cells to the corresponding carrier-hapten conjugate. In contrast, these same concentrations of free carrier failed to inhibit the T cell dependent responses of Lyb-5+ B cells to the same antigen. The inhibition of Lyb-5- B cell responses by free carrier was shown to result from active suppression mediated by carrier-specific primed Lyt-1+2- T cells and to require the additional participation of unprimed Lyt-1-2+ T cells. The activation of this suppression was antigen-specific, but suppression once activated was antigen nonspecific in its effect. These findings thus demonstrate that distinct pathways of B cell activation can be independently regulated by T suppressor network influences, and that these pathways therefore constitute potentially independent components of the immune response to a given antigenic stimulus.

Validation of Stereotyped Immunoglobulin Heavy Chain CDR3 Sequences As Candidate Antigens for Immunotherapy of CLL

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1775-1775
Author(s):  
Cristina Maccalli ◽  
Maria Gounari ◽  
Kostas Stamatopoulos ◽  
Federico Caligaris-Cappio ◽  
Giorgio Parmiani ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
Cell Cultures ◽  
Hla Class I ◽  
Class Ii ◽  
Hla Typing ◽  
Class I

Abstract Abstract 1775 The immunoglobulin gene repertoire in CLL is remarkably restricted with greater than 30% of cases carrying quasi-identical (stereotyped)heavy complementarity-determining region 3 (VH CDR3) sequences. Indeed, cases can be clustered into different subsets based on shared, subset-biased motifs within the clonotypic VH CDR3s, with, notably, only a handful of subsets accounting for almost 10% of all CLL. VH CDR3 stereotypes are more frequent in cases with unmutated IGHV genes (U-CLL) who are associated with adverse prognosis. In principle, VH CDR3 stereotypy might allow to exploit these IG motifs as candidate Tumor Associated Antigens (TAA) for targeted immunotherapy of CLL. The aim of our study was to validate as potential TAA subset-specific IG motifs from major CLL subsets, focusing especially on subsets #1 and #2 that are the largest overall and both associated with aggressive clinical course. We have so far identified, by in silico analysis, 1–3 long peptides (15-mer) encompassing the VH CDR3 protein regions of subsets #1, 2, 4, 6, 8, 10 with (i) high binding score to MHC class II molecules and (ii) also containing minimal HLA class I-specific epitopes (HLA-A2, -A3, -A24, DR1, DR7, DR13 that are most frequent in the Caucasian population). Blood lymphocytes from 18 CLL patients were collected and phenotyped by flow cytometry with appropriate antibodies to assess the expression of stimulatory, co-stimulatory and negative regulatory molecules on both T and B cells. In addition, HLA typing of CLL patients was performed to select patients expressing the aforementioned HLA molecules. Overall, 13/18 patients matched the defined HLA class I and/or class II molecules. Negatively purified T cells from 11 CLL patients expressing HLA-A2 and/or DR13 have been then stimulated in vitro with the synthesized peptides of the specific stereotype (subset #1 and 2) in the presence of culture medium containing 5% of human serum plus IL-2 (20 IU/ml) and IL-15 (10 ng/ml). These T lymphocytes were then weekly stimulated with autologous irradiated antigen presenting cells (APC; monocytes, B cells, etc.) pulsed with the peptides. Starting from the third week of culture, the specific recognition of CDR3-derived TAAs and of tumor cells (autologous CLL cells) by the T cell cultures has been assessed by in vitro functional assays (ELISPOT assay). We were able to isolate CDR3- (subsets #1 and #2) and tumor-specific T cells from 5/11 CLL patients. In addition, in 4 selected patients the Ag- and tumor specific T lymphocytes have been expanded in vitro by Rapid Expansion Protocol (REP), based on the stimulation of T cells with allogeneic irradiated PBMCs from healthy donors plus OKT3 and high doses of IL-2. Using this protocol we were able to obtain large numbers (2–10 ×109) of anti-CDR3 T cells in all 4 cases tested, thereby, in principle, achieving the potential to use this protocol for expanding sufficient cells for clinical applications. Interestingly, post-REP T cell cultures showed enrichment (85–90%) of CD3+CD8+ T cells and down-modulation of negative regulatory molecules, such as CTLA-4, as compared to pre-REP in vitro stimulated T cells. These cells could be expanded in vitro for up to 6 weeks without any decay in proliferation. Taken together, these results indicate that stereotyped VH CDR3 peptide sequences can represent candidate antigens to elicit T cell-mediated anti-CLL responses, especially in poor prognosis cases, where therapeutic innovation is more urgently needed. After validation of this protocol in a larger series, our results may provide the proof of principle for the design of new immunotherapy protocols for CLL, including both active vaccination and adoptive cell therapy. Disclosures: No relevant conflicts of interest to declare.

Bortezomib induces selective depletion of alloreactive T lymphocytes and decreases the production of Th1 cytokines

Blood ◽  
2006 ◽  
Vol 107 (9) ◽  
pp. 3575-3583 ◽  
Author(s):  
Belén Blanco ◽  
José A. Pérez-Simón ◽  
Luis I. Sánchez-Abarca ◽  
Xonia Carvajal-Vergara ◽  
Juan Mateos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nuclear Factor Κb ◽  
Third Party ◽  
Activated T Cells ◽  
Activated T Lymphocytes ◽  
Induced Apoptosis

We explored the ability of the proteasome inhibitor bortezomib, which prevents nuclear factor κB (NF-κB) activation, to block T-cell activation, proliferation, and survival within alloreactive compared with resting T cells. For this purpose, T cells were stimulated with PHA, αCD3/αCD28, or allogeneic dendritic cells or through mixed lymphocyte cultures. NF-κB expression increased in activated T lymphocytes compared with resting T cells. Of interest, the higher the NF-κB expression, the more intense the proliferative blockade induced by bortezomib. Moreover, after mixed lymphocyte reaction (MLR) cultures, alloreactive T cells were 2 logs more sensitive to bortezomib-induced apoptosis than the resting T-cell counterpart. This effect was due to a selective induction of apoptosis among activated T cells that was related to caspase activation and cleavage of the antiapoptotic bcl-2 protein and was partially abolished by the addition of the pancaspase inhibitor Z-VAD-FMK. In addition, after secondary MLR, the number of activated T cells was significantly reduced among T lymphocytes previously cultured with bortezomib when cells from the same donor were used as stimulating cells. By contrast, when third-party donor cells were used as stimulating cells, no significant differences were observed between T lymphocytes previously exposed or not to the drug, indicating a highly specific depletion of T lymphocytes alloreactive against primary donor antigens. The addition of bortezomib decreased not only the proliferation and viability of activated T lymphocytes but also the levels of IFNγ and IL-2, which were significantly decreased among activated T cells cultured with bortezomib at doses ranging from 10 to 100 nM. In conclusion, at concentrations reached in the clinical setting, bortezomib induces selective apoptosis and decreases Th1 response among alloreactive T lymphocytes while it barely affects unstimulated T cells. These results establish the basis for the clinical use of bortezomib in the management of graft-versus-host disease (GVHD).

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