scholarly journals Aloperine Protects Mice against DSS-Induced Colitis by PP2A-Mediated PI3K/Akt/mTOR Signaling Suppression

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaoxia Fu ◽  
Fei Sun ◽  
Faxi Wang ◽  
Junai Zhang ◽  
Biying Zheng ◽  
...  
Keyword(s):  
T Cell ◽  
Molecular Mechanisms ◽  
Mononuclear Cells ◽  
Intestinal Inflammation ◽  
Inflammatory Responses ◽  
Activity Index ◽  
Mtor Signaling ◽  
Jurkat Cells ◽  
Dependent Manner ◽  
Activated T Cells

Colitis is a major form of inflammatory bowel disease which involved mucosal immune dysfunction. Aloperine is an alkaloid isolated from the shrub Sophora alopecuroides L. and has been recognized as an effective treatment for inflammatory and allergic diseases. The present study aimed to examine the molecular mechanisms underlying aloperine-mediated colitis protection. We found that aloperine treatment improved colitis induced by dextran sodium sulfate (DSS) based on body weight, disease activity index, colonic length, and spleen index. Aloperine also effectively attenuated DSS-induced intestinal inflammation based on the pathological score and myeloperoxidase expression and activity in colon tissues. In addition, aloperine regulated T-cell proportions and promoted Foxp3 expression in the spleens and mesenteric lymph nodes of DSS-induced colitis mice and in the spleens of the Foxp3GFP mice. Aloperine inhibited Jurkat and mouse naïve T-cell apoptosis. Furthermore, aloperine inhibited PI3K/Akt/mTOR signaling and upregulated PP2A expression in the DSS-induced colitis mice and in Jurkat cells, but LB-100 (PP2A inhibitor) resulted in an elevated Akt activity in Jurkat cells, activated T-cells, and human splenic mononuclear cells. Aloperine inhibited T-cell and lymphocyte proliferation, but LB-100 reverse these effects. In conclusion, aloperine regulates inflammatory responses in colitis by inhibiting the PI3K/Akt/mTOR signaling in a PP2A-dependent manner.

Activated T Cell-Mediated Immunotherapy with a Chimeric Receptor Against CD38 in B-Cell Malignancies.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2356-2356
Author(s):  
Keichiro Mihara ◽  
Kazuyoshi Yanagihara ◽  
Misato Takigahira ◽  
Takahiro Ochiya ◽  
Chihaya Imai ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Jurkat Cells ◽  
Steady Increase ◽  
Dependent Manner ◽  
Chimeric Receptor ◽  
Activated T Cells ◽  
Peripheral T Cells

Abstract CD38 is expected to be one of the most useful molecular targets on the surface of malignant B-cells. T cell-mediated immunotherapy with a chimeric receptor could provide a powerful tool for treating cancer. However, since CD38 is also expressed on effector cells such as activated T cells, NK cells, and monocytes, these cells with the chimeric receptor could be eliminated by autologous cytotoxicity through the interaction with the antigen. In this study, we developed a novel methodology for enhancing the survival and clonal expansion of T lymphocytes expressing an anti-CD38 chimeric receptor. Hut78 T cells, which express very little CD38, retrovirally transduced with the anti-CD38 chimeric receptor showed powerful cytotoxic activity against B cell lines expressing CD38, such as HT (lymphoma), RPMI8226 (myeloma), 380 (ALL-Ph1−) and OP-1 (ALL-Ph1+) cells (mean specific cytotoxicity was 97.94% ± 0.31% after four days of culture in vitro). However, in activated human T cells and Jurkat cells constitutively expressing CD38, the recovery rate of cells transduced with the chimeric receptor was extremely low, because the cells eradicated each other and/or themselves by inducing apoptosis. To block the interaction of the anti-CD38 chimeric receptor with CD38 antigen, we incubated activated T cells and Jurkat cells in medium supplemented with an anti-CD38 antibody before the transduction. The number of viable cells harvested after the transduction was dramatically increased by the antibody in a dose-dependent manner. Using this method, we prepared human peripheral T cells bearing the chimeric receptor and injected them into NOD/SCID mice, which were transplanted with HT cells labeled with luciferase. Lucuferase activity was not detectable in 13 days in five of six mice with T cells transduced with the chimeric receptor. In contrast, the activity had a rapid and steady increase in all of the mice injected with vector-transduced T cells. These results clearly showed that even though human peripheral T cells express any molecule on their surface, an antibody could protect T cells transduced with a chimeric receptor-containing vector from cytolysis, and apoptosis. These findings may provide us with a powerful tool for improving T cell-mediated targeting therapy.

scholarly journals Targeting CD38 is lethal to Breg-like chronic lymphocytic leukemia cells and Tregs, but restores CD8+ T-cell responses

2020 ◽  
Vol 4 (10) ◽  
pp. 2143-2157 ◽  
Author(s):  
Alak Manna ◽  
Timothy Kellett ◽  
Sonikpreet Aulakh ◽  
Laura J. Lewis-Tuffin ◽  
Navnita Dutta ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Lymphocytic Leukemia ◽  
Dependent Manner

Abstract Patients with chronic lymphocytic leukemia (CLL) are characterized by monoclonal expansion of CD5+CD23+CD27+CD19+κ/λ+ B lymphocytes and are clinically noted to have profound immune suppression. In these patients, it has been recently shown that a subset of B cells possesses regulatory functions and secretes high levels of interleukin 10 (IL-10). Our investigation identified that CLL cells with a CD19+CD24+CD38hi immunophenotype (B regulatory cell [Breg]–like CLL cells) produce high amounts of IL-10 and transforming growth factor β (TGF-β) and are capable of transforming naive T helper cells into CD4+CD25+FoxP3+ T regulatory cells (Tregs) in an IL-10/TGF-β-dependent manner. A strong correlation between the percentage of CD38+ CLL cells and Tregs was observed. CD38hi Tregs comprised more than 50% of Tregs in peripheral blood mononuclear cells (PBMCs) in patients with CLL. Anti-CD38 targeting agents resulted in lethality of both Breg-like CLL and Treg cells via apoptosis. Ex vivo, use of anti-CD38 monoclonal antibody (mAb) therapy was associated with a reduction in IL-10 and CLL patient-derived Tregs, but an increase in interferon-γ and proliferation of cytotoxic CD8+ T cells with an activated phenotype, which showed an improved ability to lyse patient-autologous CLL cells. Finally, effects of anti-CD38 mAb therapy were validated in a CLL–patient-derived xenograft model in vivo, which showed decreased percentage of Bregs, Tregs, and PD1+CD38hiCD8+ T cells, but increased Th17 and CD8+ T cells (vs vehicle). Altogether, our results demonstrate that targeting CD38 in CLL can modulate the tumor microenvironment; skewing T-cell populations from an immunosuppressive to immune-reactive milieu, thus promoting immune reconstitution for enhanced anti-CLL response.

scholarly journals Molecular cloning of a novel human cDNA encoding a zinc finger protein that binds to the interleukin-3 promoter.

1994 ◽  
Vol 14 (8) ◽  
pp. 5099-5107 ◽  
Author(s):  
N Koyano-Nakagawa ◽  
J Nishida ◽  
D Baldwin ◽  
K Arai ◽  
T Yokota
Keyword(s):  
T Cell ◽  
Zinc Finger ◽  
Transcriptional Activity ◽  
Regulatory Region ◽  
Jurkat Cells ◽  
Type I ◽  
Dependent Manner ◽  
Cell Leukemia Virus Type ◽  
Transcription Activity ◽  
Interleukin 3

The CT/GC-rich region (-76 to -47) is one transcriptional regulatory region of the interleukin-3 (IL-3) gene which confers basic transcriptional activity and responds to trans-activation by human T-cell leukemia virus type I-encoded Tax. We isolated three types of cDNAs encoding Cys2/His2-type zinc finger proteins that bind to this region. Two were identical to known transcription factors, EGR1 and EGR2, and the other clone, named DB1, encoded a novel protein of 516 amino acids with six zinc finger motifs. DB1 mRNA was present in human tissues, ubiquitously. Two constitutive transcripts of 4.0 and 4.8 kb in length were present in Jurkat cells. Electrophoretic mobility shift assay, with specific antibodies, showed that DB1 constitutively binds to this region whereas EGR1 binds in a T-cell activation-dependent manner. Overexpression of DB1 in Jurkat cells had no detectable effect on the transcription activity of the IL-3 promoter, in a transient-transfection assay. EGR1 and EGR2 increased IL-3 promoter activity when the transfected cells were stimulated with phorbol-12-myristate-13-acetate and A23187. When DB1 was cotransfected with a Tax expression vector, transcription activity of the IL-3 promoter induced by Tax was significantly increased, while EGR1 and EGR2 were without effect. These results suggest that EGR1 has a role in inducible transcription of the IL-3 gene, while DB1 sustains basal transcriptional activity and also cooperates with Tax to activate the IL-3 promoter.

scholarly journals Prolonged activation of nasal immune cell populations and development of tissue-resident SARS-CoV-2 specific CD8 T cell responses following COVID-19

2021 ◽  
Author(s):  
Anna H.E. Roukens ◽  
Marion König ◽  
Tim Dalebout ◽  
Tamar Tak ◽  
Shohreh Azimi ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Nasal Mucosa ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Upper Airway ◽  
Effector Memory ◽  
Long Term Effects ◽  
Activated T Cells

AbstractThe immune system plays a major role in Coronavirus Disease 2019 (COVID-19) pathogenesis, viral clearance and protection against re-infection. Immune cell dynamics during COVID-19 have been extensively documented in peripheral blood, but remain elusive in the respiratory tract. We performed minimally-invasive nasal curettage and mass cytometry to characterize nasal immune cells of COVID-19 patients during and 5-6 weeks after hospitalization. Contrary to observations in blood, no general T cell depletion at the nasal mucosa could be detected. Instead, we observed increased numbers of nasal granulocytes, monocytes, CD11c+ NK cells and exhausted CD4+ T effector memory cells during acute COVID-19 compared to age-matched healthy controls. These pro-inflammatory responses were found associated with viral load, while neutrophils also negatively correlated with oxygen saturation levels. Cell numbers mostly normalized following convalescence, except for persisting CD127+ granulocytes and activated T cells, including CD38+ CD8+ tissue-resident memory T cells. Moreover, we identified SARS-CoV-2 specific CD8+ T cells in the nasal mucosa in convalescent patients. Thus, COVID-19 has both transient and long-term effects on the immune system in the upper airway.

CD4+ T cells are essential for the development of destructive thyroiditis induced by anti–PD-1 antibody in thyroglobulin-immunized mice

2021 ◽  
Vol 13 (593) ◽  
pp. eabb7495
Author(s):  
Yoshinori Yasuda ◽  
Shintaro Iwama ◽  
Daisuke Sugiyama ◽  
Takayuki Okuji ◽  
Tomoko Kobayashi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Mononuclear Cells ◽  
Critical Role ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Histopathological Analysis ◽  
Activated T Cells ◽  
Cervical Lymph Nodes

Immune-related adverse events induced by anti–programmed cell death–1 antibodies (PD-1-Ab), including destructive thyroiditis (thyroid-irAE), are thought to be caused by activated T cells. However, the T cell subsets that are directly responsible for damaging self-organs remain unclear. To clarify which T cell subsets are involved in the development of thyroid-irAE, a mouse model of thyroid-irAE was analyzed. PD-1-Ab administration 2.5 months after immunization with thyroglobulin caused destructive thyroiditis. Thyroiditis was completely prevented by previous depletion of CD4+ T cells and partially prevented by depleting CD8+ T cells. The frequencies of central and effector memory CD4+ T cell subsets and the secretion of interferon-γ after stimulation with thyroglobulin were increased in the cervical lymph nodes of mice with thyroid-irAE compared with controls. Histopathological analysis revealed infiltration of CD4+ T cells expressing granzyme B in thyroid glands and major histocompatibility complex class II expression on thyrocytes in mice with thyroid-irAE. Adoptive transfer of CD4+ T cells from cervical lymph nodes in mice with thyroid-irAE caused destruction of thyroid follicular architecture in the irradiated recipient mice. Flow cytometric analyses showed that the frequencies of central and effector memory CD4+ T cells expressing the cytotoxic marker CD27 were higher in peripheral blood mononuclear cells collected from patients with thyroid-irAE induced by PD-1-Ab versus those without. These data suggest a critical role for cytotoxic memory CD4+ T cells activated by PD-1-Ab in the pathogenesis of thyroid-irAE.

scholarly journals Maltol Improves APAP-Induced Hepatotoxicity by Inhibiting Oxidative Stress and Inflammation Response via NF-κB and PI3K/Akt Signal Pathways

Antioxidants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 395 ◽  
Author(s):  
Zi Wang ◽  
Weinan Hao ◽  
Junnan Hu ◽  
Xiaojie Mi ◽  
Ye Han ◽  
...  
Keyword(s):  
Liver Injury ◽  
Protective Effect ◽  
Molecular Mechanisms ◽  
Inflammatory Responses ◽  
B Cell Lymphoma ◽  
Inflammatory Factors ◽  
Signal Pathways ◽  
Dependent Manner ◽  
Beneficial Effects

Maltol, a food-flavoring agent and Maillard reaction product formed during the processing of red ginseng (Panax ginseng, C.A. Meyer), has been confirmed to exert a hepatoprotective effect in alcohol-induced oxidative damage in mice. However, its beneficial effects on acetaminophen (APAP)-induced hepatotoxicity and the related molecular mechanisms remain unclear. The purpose of this article was to investigate the protective effect and elucidate the mechanisms of action of maltol on APAP-induced liver injury in vivo. Maltol was administered orally at 50 and 100 mg/kg daily for seven consecutive days, then a single intraperitoneal injection of APAP (250 mg/kg) was performed after the final maltol administration. Liver function, oxidative indices, inflammatory factors—including serum alanine and aspartate aminotransferases (ALT and AST), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), liver glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), cytochrome P450 E1 (CYP2E1) and 4-hydroxynonenal (4-HNE) were measured. Results demonstrated that maltol possessed a protective effect on APAP-induced liver injury. Liver histological changes and Hoechst 33258 staining also provided strong evidence for the protective effect of maltol. Furthermore, a maltol supplement mitigated APAP-induced inflammatory responses by increasing phosphorylated nuclear factor-kappa B (NF-κB), inhibitor kappa B kinase α/β (IKKα/β), and NF-kappa-B inhibitor alpha (IκBα) in NF-κB signal pathways. Immunoblotting results showed that maltol pretreatment downregulated the protein expression levels of the B-cell-lymphoma-2 (Bcl-2) family and caspase and altered the phosphorylation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) in a dose-dependent manner. In conclusion, our findings clearly demonstrate that maltol exerts a significant liver protection effect, which may partly be ascribed to its anti-inflammatory and anti-apoptotic action via regulation of the PI3K/Akt signaling pathway.

scholarly journals ICOSLG-mediated regulatory T cell expansion and IL-10 production promote progression of glioblastoma

2019 ◽  
Author(s):  
Ryoichi Iwata ◽  
Joo Hyoung Lee ◽  
Mikio Hayashi ◽  
Umberto Dianzani ◽  
Kohei Ofune ◽  
...  
Keyword(s):  
T Cell ◽  
Molecular Mechanisms ◽  
Interleukin 10 ◽  
Dependent Manner ◽  
Gene Encoding ◽  
Checkpoint Proteins ◽  
Underlying Mechanisms ◽  
Immune Checkpoint Proteins ◽  
Factor Α ◽  
Regulatory Ligands

Abstract Background Targeting immune checkpoint proteins has recently gained substantial attention due to the dramatic success of this strategy in clinical trials for some cancers. Inducible T-cell co-stimulator ligand (ICOSLG) is a member of the B7 family of immune regulatory ligands, expression of which in cancer is implicated in disease progression due to regulation of anti-tumor adaptive immunity. Although aberrant ICOSLG expression has been reported in glioma cells, the underlying mechanisms that promote glioblastoma (GBM) progression remain elusive. Methods Here, we investigated a causal role for ICOSLG in GBM progression by analyzing ICOSLG expression in both human glioma tissues and patient-derived GBM sphere cells (GSCs). We further examined its immune modulatory effects and the underlying molecular mechanisms. Results Bioinformatics analysis and GBM tissue microarray showed that upregulation of ICOSLG expression was associated with poor prognosis in patients with GBM. ICOSLG expression was upregulated preferentially in mesenchymal GSCs but not in proneural GSCs in a tumor necrosis factor-α-/NF-ĸB-dependent manner. Furthermore, ICOSLG expression by mesenchymal GSCs promoted expansion of T cells that produced interleukin-10. Knockdown of the gene encoding ICOSLG markedly reduced GBM tumor growth in immune competent mice, with a concomitant downregulation of interleukin-10 levels in the tumor microenvironment. Conclusions Inhibition of the ICOSLG-ICOS axis in GBM may provide a promising immunotherapeutic approach for suppressing a subset of GBM with an elevated mesenchymal signature.

scholarly journals Selective Upregulation of Transcripts for Six Molecules Related to T Cell Costimulation and Phagocyte Recruitment and Activation among 734 Immunity-Related Genes in the Brain during Perforin-Dependent, CD8+ T Cell-Mediated Elimination of Toxoplasma gondii Cysts

mSystems ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Jenny Lutshumba ◽  
Eri Ochiai ◽  
Qila Sa ◽  
Namrata Anand ◽  
Yasuhiro Suzuki
Keyword(s):  
T Cells ◽  
T Cell ◽  
Toxoplasma Gondii ◽  
Molecular Mechanisms ◽  
Cytotoxic T Cells ◽  
Scid Mice ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Content Type ◽  
Immune Related Genes

ABSTRACT We recently found that an invasion of CD8+ cytotoxic T cells into tissue cysts of Toxoplasma gondii initiates an elimination of the cysts in association with an accumulation of microglia and macrophages. In the present study, we compared mRNA levels for 734 immune-related genes in the brains of infected SCID mice that received perforin-sufficient or -deficient CD8+ immune T cells at 3 weeks after infection. At 7 days after the T cell transfer, mRNA levels for only six genes were identified to be greater in the recipients of the perforin-sufficient T cells than in the recipients of the perforin-deficient T cells. These six molecules included two T cell costimulatory molecules, inducible T cell costimulator receptor (ICOS) and its ligand (ICOSL); two chemokine receptors, C-X-C motif chemokine receptor 3 (CXCR3) and CXCR6; and two molecules related to an activation of microglia and macrophages, interleukin 18 receptor 1 (IL-18R1) and chitinase-like 3 (Chil3). Consistently, a marked reduction of cyst numbers and upregulation of ICOS, CXCR3, CXCR6, IL-18R1, and Chil3 mRNA levels were also detected when the perforin-sufficient CD8+ immune T cells were transferred to infected SCID mice at 6 weeks after infection, indicating that the CD8+ T cell-mediated protective immunity is capable of eliminating mature T. gondii cysts. These results together suggest that ICOS-ICOSL interactions are crucial for activating CD8+ cytotoxic immune T cells to initiate the destruction of T. gondii cysts and that CXCR3, CXCR6, and IL-18R are involved in recruitment and activation of microglia and macrophages to the T cell-attacked cysts for their elimination. IMPORTANCE T. gondii establishes a chronic infection by forming tissue cysts, which can grow into sizes greater than 50 μm in diameter as a consequence of containing hundreds to thousands of organisms surrounded by the cyst wall within infected cells. Our recent studies using murine models uncovered that CD8+ cytotoxic T cells penetrate into the cysts in a perforin-dependent manner and induce their elimination, which is accompanied with an accumulation of phagocytic cells to the T cell-attacked target. This is the first evidence of the ability of the T cells to invade into a large target for its elimination. However, the mechanisms involved in anticyst immunity remain unclear. Immune profiling analyses of 734 immune-related genes in the present study provided a valuable foundation to initiate elucidating detailed molecular mechanisms of the novel effector function of the immune system operated by perforin-mediated invasion of CD8+ T cells into large targets for their elimination.

scholarly journals CXCL1 contributes to IL-6 expression in osteoarthritis and rheumatoid arthritis synovial fibroblasts by CXCR2, c-Raf, MAPK, and AP-1 pathway

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Sheng-Mou Hou ◽  
Po-Chun Chen ◽  
Chieh-Mo Lin ◽  
Mei-Ling Fang ◽  
Miao-Ching Chi ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Proinflammatory Cytokine ◽  
Molecular Mechanisms ◽  
Inflammatory Responses ◽  
Synovial Fibroblasts ◽  
Dependent Manner ◽  
Tissue Samples ◽  
Chemical Inhibitors ◽  
Shrna Plasmid ◽  
Signal Cascades

Abstract Background Osteoarthritis (OA) and rheumatoid arthritis (RA) are common joint disorders that are considered to be different diseases due to their unique molecular mechanisms and pathogenesis. Chemokines and their corresponding receptors have been well characterized in RA progression, but less so in OA pathogenesis. Methods The human primary synovial fibroblasts (SFs) were obtained from human OA and RA tissue samples. The Western blot and qPCR were performed to analyze the expression levels of CXCL1, as well as CXCL-promoted IL-6 expression in both OASFs and RASFs. The signal cascades that mediate the CXCL1-promoted IL-6 expression were identified by using chemical inhibitors, siRNAs, and shRNAs. Results Here, we found that both diseases feature elevated levels of CXCL1 and interleukin (IL)-6, an important proinflammatory cytokine that participates in OA and RA pathogenesis. In OASFs and RASFs, CXCL1 promoted IL-6 expression in a dose- and time-dependent manner. In OASFs and RASFs overexpressing CXCL1 or transduced with shRNA plasmid, IL-6 expression was markedly upregulated. CXCR2, c-Raf, and MAPKs were found to regulate CXCL1-induced IL-6 expression in OASFs and RASFs. Finally, CXCL1 triggered the transcriptional activities of c-Jun (which regulates the expression of proinflammatory proteins) in OASFs and RASFs. Conclusions Our present work suggests that the CXCL1/CXCR2 axis helps to orchestrate inflammatory responses in OA and RA SFs.

scholarly journals Daclizumab reduces CD25 levels on T cells through monocyte-mediated trogocytosis

2013 ◽  
Vol 20 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Y Zhang ◽  
M McClellan ◽  
L Efros ◽  
D Shi ◽  
B Bielekova ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
Interleukin 2 ◽  
Treg Cells ◽  
Activated T Cells ◽  
Peripheral Blood Mononuclear ◽  
Dependent Relationship ◽  
Cell Counts ◽  
Humanized Monoclonal Antibody

Daclizumab is a humanized monoclonal antibody that prevents interleukin-2 (IL-2) binding to CD25, blocking IL-2 signaling by cells that require high-affinity IL-2 receptors to mediate IL-2 signaling. The phase 2a CHOICE study evaluating daclizumab as a treatment for multiple sclerosis (MS) included longitudinal analysis of activated T cell counts. Whereas an exposure-dependent relationship was observed between daclizumab and reductions in HLA-DR+-activated T cells, a similar relationship was not observed for reductions in CD25 levels. The objective of this report is to determine the mechanism by which daclizumab reduces CD25 levels on peripheral blood mononuclear cells (PBMCs) using cytometric techniques. Daclizumab reduced T cell CD25 levels through a mechanism that required the daclizumab-Fc domain interaction with Fc receptors (FcR) on monocytes, but not on natural killer (NK) cells, and was unrelated to internalization or cell killing. Activated CD4+ T cells and FoxP3+ Treg cells showed evidence of trogocytosis of the CD25 antigen in the presence of monocytes. A daclizumab variant that retained affinity for CD25 but lacked FcR binding did not induce trogocytosis and was significantly less potent as an inhibitor of IL-2-induced proliferation of PBMCs. In conclusion, Daclizumab-induced monocyte-mediated trogocytosis of CD25 from T cells appears to be an additional mechanism contributing to daclizumab inhibition of IL-2 signaling.

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