• IMMUNE NETWORK
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• v.11 no.6
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• pp.406-411
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• 2011

Background: Invariant Natural killer T (iNKT) cells, a distinct subset of CD1d-restricted T cells with invariant $V{\alpha}{\beta}$ TCR, functionally bridge innate and adaptive immunity. While iNKT cells share features with conventional T cells in some functional aspects, they simultaneously produce large amount of Th1 and Th2 cytokines upon T-cell receptor (TCR) ligation. However, gene expression pattern in two types of cells has not been well characterized. Methods: we performed comparative microarray analyses of gene expression in murine iNKT cells and conventional $CD4^+CD25^-$ ${\gamma}{\delta}TCR^-$ T cells by using Gene Set Enrichment Analysis (GSEA) method. Results: Here, we describe profound differences in gene expression pattern between iNKT cells and conventional $CD4^+CD25^-$ ${\gamma}{\delta}TCR^-$ T cells. Conclusion: Our results provide new insights into the functional competence of iNKT cells and a better understanding of their various roles during immune responses.

• Molecules and Cells
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• v.40 no.1
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• pp.37-44
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• 2017

PDK1 is essential for T cell receptor (TCR)-mediated activation of $NF-{\kappa}B$, and PDK1-induced phosphorylation of $PKC{\theta}$ is important for TCR-induced $NF-{\kappa}B$ activation. However, inverse regulation of PDK1 by $PKC{\theta}$ during T cell activation has not been investigated. In this study, we found that $PKC{\theta}$ is involved in human PDK1 phosphorylation and that its kinase activity is crucial for human PDK1 phosphorylation. Mass spectrometry analysis of wild-type $PKC{\theta}$ or of kinase-inactive form of $PKC{\theta}$ revealed that $PKC{\theta}$ induced phosphorylation of human PDK1 at Ser-64. This $PKC{\theta}$-induced PDK1 phosphorylation positively regulated T cell activation and TCR-induced $NF-{\kappa}B$ activation. Moreover, phosphorylation of human PDK1 at Ser-64 increased the stability of human PDK1 protein. These results suggest that Ser-64 is an important phosphorylation site that is part of a positive feedback loop for human PDK1-$PKC{\theta}$-mediated T cell activation.

• Molecules and Cells
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• v.20 no.3
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• pp.339-347
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• 2005

IL-17 (IL-17A or CTLA-8) is the founding member of a novel family of inflammatory cytokines, and emerging evidence indicates that it plays a central role in inflammation and autoimmunity. IL-17 is made primarily, if not exclusively by T cells, but relatively little is known about how its expression is regulated. In the present study, we examined the requirements and mechanisms for IL-17 expression in primary mouse lymphocytes. Like many cytokines, IL-17 is induced rapidly in primary T cells after stimulation of the T cell receptor (TCR) through CD3 crossinking. Surprisingly, however, the pattern of regulation of IL-17 is different in mice than in humans, because "costimulation" of T cells through CD28 only mildly enhanced IL-17 expression, whereas levels of IL-2 were dramatically enhanced. Similarly, several other costimulatory molecules such as ICOS, 4-1BB and CD40L exerted only very weak enhancing effects on IL-17 production. In agreement with other reports, IL-23 enhanced CD3-induced IL-17 expression. However, IL-17 production can occur autonomously in T cells, as neither dendritic cells nor IL-23 were necessary for promoting short-term production of IL-17. Finally, to begin to characterize the TCR-mediated signaling pathway(s) required for IL-17 production, we showed that IL-17 expression is sensitive to cyclosporin-A and MAPK inhibitors, suggesting the involvement of the calcineurin/NFAT and MAPK signaling pathways.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2909-2916
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• 2016

Background: Canine malignant lymphoma is classified into B- or T-cell origin, as in the human case. Due to differences in prognosis, a suitable method needs to be developed for lineage identification. Aims: To determine the accuracy of immunophenotypic and molecular information between three methods: immunocytochemistry (ICC), immunohistochemistry (IHC) and heteroduplex polymerase chain reaction for antigen receptor rearrangements (hPARR) in spontaneous canine lymphomas. Materials and Methods: Peripheral blood, fine needle aspiration and tissue biopsies from enlarged peripheral lymph nodes prior to treatment of 28 multicentric lymphoma patients were collected. Cytopathology and histopathology were examined and classified using the updated Kiel and WHO classifications, respectively. Anti-Pax5 and anti-CD3 antibodies as B- and T-cell markers were applied for immunophenotyping by ICC and IHC. Neoplastic lymphocytes from lymph node and white blood cell pellets from peripheral blood were evaluated by hPARR. Results: In this study, low grade B-cell lymphoma accounted for 25% (7/28), high grade B-cell lymphoma for 64.3% (18/28) and high grade T-cell lymphoma for 10.7% (3/28). According to the WHO classification, 50% of all cases were classified as diffuse large B-cell lymphoma. In addition, ICC showed concordant results with IHC; all B-cell lymphomas showed Pax5+/CD3, and all T-cell lymphomas exhibited Pax5-/CD3+. In contrast to hPARR, 12 B-cell lymphomas featured the IgH gene; seven presented the $TCR{\gamma}$ gene; five cases showed both IgH and $TCR{\gamma}$ genes, and one case were indeterminate. Three T-cell lymphomas showed the $TCR{\gamma}$ gene. The percentage agreement between hPARR and ICC/IHC was 60%. Conclusions: Immunophenotyping should not rely on a single method. ICC or IHC with hPARR should be used concurrently for immunophenotypic diagnosis in canine lymphomas.

• Molecules and Cells
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• v.28 no.3
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• pp.183-188
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• 2009

TSAd/Lad is a T cell adaptor molecule involved in $p56^{lck}$-mediated T cell activation. To investigate the functions of TSAd in T cells, we generated transgenic (TG) mice expressing the SH2 domain of TSAd (TSAd-SH2) under the control of the $p56^{lck}$ proximal promoter. In T cells from TSAd-SH2 TG mice, T cell receptor (TCR)-mediated early signaling events, such as $Ca^{2+}$ flux and ERK activation, were normal; however, late activation events, such as IL-2 production and proliferation, were significantly reduced. Moreover, TCR-induced cell adhesion to extracellular matrix (ECM) proteins and migration through ECM proteins were defective in T cells from TSAd-SH2 TG mice. Furthermore, the contact hypersensitivity (CHS) reaction, an inflammatory response mainly mediated by T helper 1 (Th1) cells, was inhibited in TSAd-SH2 TG mice. Taken together, these results show that TSAd, particularly the SH2 domain of TSAd, is essential for the effector functions of T cells.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.505-513
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• 2021

Objective : The adaptive immune response following subarachnoid hemorrhage (SAH) is not well understood. We evaluated and compared the T cell receptor (TCR) immune repertoire of good-grade and poor-grade SAH patients to elucidate the T cell immunology after ictus. Methods : Peripheral blood from six SAH patients was collected at two different times, admission and at the 7-day follow-up. Composition and variation of the TCR β-chain (TCRB) complimentary determining regions (CDR) 3 repertoire was examined using high-throughput sequencing; the analysis was based on sampling time and disease severity (good vs. poor-grade SAH). Results : Clonality at admission and follow-up were 0.059 (0.037-0.038) and 0.027 (0.014-0.082) (median, 25th-75th percentile). Poor-grade SAH (0.025 [0.011-0.038]) was associated with significantly lower clonality than good-grade SAH (0.095 [0.079-0.101]). Poor-grade SAH patients had higher diversity scores than good-grade SAH patients. CDR length was shorter in good-grade SAH vs. poor-grade SAH. Differences in clonotype distribution were more prominent in TCRBV gene segments than TCRBJ segments. TCRBV19-01/TCRBJ02-04 and TCRBV28-01/TCRBJ02-04 were the most increased and the most decreased V-J pairs in the 7-day follow-up compared to admission in good-grade SAH. The most increased and decreased V-J pairs in poor-grade SAH patients were TCRBV28-01/TCRBJ02-06 and TCRBV30-01/TCRBJ02-04, respectively. Conclusion : The TCRB repertoire is dynamic in nature following SAH. TCRB repertoire may facilitate our understanding of adaptive immune response according to SAH severity.

• Journal of Ginseng Research
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• v.19 no.2
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• pp.117-121
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• 1995

We studied the effects of ginsenoside-$Rg_1$ (G-$Rg_1$) extracted from Panax ginseng C.A. Meyer on $p56^{kk}$ kinase and cell proliferation in Jurkat T cells. $p56^{kk}$ was maximally activated within 5 min after the treatment of 16.7 $\mu\textrm{g}$/ml of G-$Rg_1$ increasing the activity by 1.2-2 times relative to untreated control, thereafter its activity was gradually decreased to the level of untreated control. The action of EGTA on the kinase was altered by the addition of G-$Rg_1$, accompanying the band shift of $p56^{kk}$ to $p60^{kk}$. In addition, G-$Rg_1$promoted cell proliferation in a concentration-dependent manner. These results suggest that G-$Rg_1$ may be involved in T cell receptor-CD3 (TCR) signaling via the activation of $p56^{kk}$ and the chance of cellular calcium concentration.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.361-373
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• 2020

Integrins such as lymphocyte function-associated antigen -1 (LFA-1) have an essential role in T cell immunity. Integrin activation, namely, the transition from the inactive conformation to the active one, takes place when an intracellular signal is generated by specific receptors such as T cell receptors (TCRs) and chemokine receptors in T cells. In an effort to explore the molecular mechanisms underlying the TCR-mediated LFA-1 activation, we had previously established a high-throughput cell-based assay and screened a chemical library deposited in the National Institute of Health in the United States. As a result, several hits had been isolated including HIKS-1 (Benzo[b]thiophene-3-carboxylic acid, 2-[3-[(2-carboxyphenyl) thio]-2,5-dioxo-1-pyrrolinyl]-4,5,6,7-tetrahydro-,3-ethyl ester). In an attempt to reveal the mode of action of HIKS-1, in this study, we did drug affinity responsive target stability (DARTS) assay finding that HIKS-1 interacted with the IQ motif containing GTPase activating protein 1 (IQGAP1), a 189 kDa multidomain scaffold protein critically involved in various signaling mechanisms. Furthermore, the cellular thermal shift assay (CETSA) provided compelling evidence that HIKS-1 also interacted with IQGAP1 in vivo. Taken together, it can be concluded that HIKS-1 interferes with the TCR-mediated LFA-1 activation by interacting with IQGAP1 and thereby disrupting the signaling pathway for LFA-1 activation.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.95-103
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• 2001

T cells play a central role in the initiation and regulation of the immune response to foreign antigens. Full activation of T cells requires the engagement of T cell receptor complex (TCR) and the binding of a second costimulatory receptor to its ligand expressed on antigen presenting cells (APC). Among the molecules known to provide costimulatory function, CD28 has been the most dominant and potent costimulatory molecule. However, the function of CD28 is becoming more complex due to the recent discovery of its structural homologue, CTLA-4 and ICOS. This review summarizes the biology and physiologic function of each of these receptors, and further focuses on the biochemical mechanism underlying the function of these receptors. Complete understanding of the CD28/CTLA-4/ICOS costimulatory pathway will provide the basis for developing new therapeutic approaches for immunological dieseases.

• IMMUNE NETWORK
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• v.23 no.5
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• pp.37.1-37.11
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• 2023

Forkhead box P3-positive (Foxp3⁺)-inducible Tregs (iTregs) are readily generated by TGF-β1 at low TCR signaling intensity. TGF-β1-mediated Foxp3 expression is further enhanced by retinoic acid (RA) and lactoferrin (LF). However, the intensity of TCR signaling required for induction of Foxp3 expression by TGF-β1 in combination with RA and LF is unknown. Here, we found that either RA or LF alone decreased TGF-β1-mediated Foxp3 expression at low TCR signaling intensity. In contrast, at high TCR signaling intensity, the addition of either RA or LF strongly increased TGF-β1-mediated Foxp3 expression. Moreover, decreased CD28 stimulation was more favorable for TGF-β1/LF-mediated Foxp3 expression. Lastly, we found that at high signaling intensities of both TCR and CD28, combined treatment with TGF-β1, RA, and LF induced robust expression of Foxp3, in parallel with powerful suppressive activity against responder T cell proliferation. Our findings that TGFβ/RA/LF strongly generate high affinity Ag-specific iTreg population would be useful for the control of unwanted hypersensitive immune reactions such as various autoimmune diseases.