Polarization of T helper Cells Depends on the Presence of Antigen Presentation / 대한면역학회지

There are strong evidences suggesting that Thl and Th2 lymphocytes develop from the same Thlymphocyte precursor under the influence of environmental or genetic factors acting at the level of antigen presentation, but it remains to be answered whether it is possible to change the cytokine profile of established or ongoing Th1 and Th2 response. The purpose of this study is to reveal whether it is possible to reverse the cytokine profile of human Th lymphocytes by the modulation of antigen presentation. Using a multiparameter flow cytometric assay that allows simultaneous determination of surface CD4 and intracellular IFN-r or IL-4, we have studied the emergence of Th1 or Th2 lymphocytes in response to tetanus toxoid exposure and the patterns of cytokine synthesis in established T lymphocyte clones. Th2 populations arising after 4 wk of stimulation in IL-2, PHA, tetanus toxoid and irradiated autogeneic peripheral blood mononuclear cells as antigen presenting cells (APC) could give rise to IFN-r-producing Th1 lymphocytes when stimulated in IL-2 plus PHA in the absence of antigen and APC. These IFN-r-producing Th1 lymphocytes nearly disappeared and IL-4-producing Th2 lymphocytes predominated again when cultured again in the presence of antigen and APC. In contrast, prolonged culture in the absence of antigen and APC induced relative predominance of IFN-r-producing The lymphocytes. The cytokine profile of long-term Th2 population arising originally from the repeated stimulation in the presence of antigen and APC appeared more homogeneous and less reversible, although they could convert to Th1 lymphocytes when cultured without antigen and APC. These findings may explain that the polarized Th response is reversible depending on the presence of antigen presentation.

Hormonal and Cytokine Regulation of ICAM-1 gene in FRTL-5 Thyroid Cells: Cloning and Analysis of 5-Regulatory Region of Rat ICAM-1 Gene / 대한내분비학회지

BACKGROUND: We have found abnormal expression of ICAM-1 in thyroid follicular cells from patients with Graves disease and Hashimoto disease. In this report, we present the hormonal regulation of ICAM-1 mRNA expression and the primary structure of 5-regulatory region which is important for transcriptional regulation of ICAM-1 gene. A I.S kb fragment of the 5-regulatory sequences are identified and linked to luciferase as a reporter. METHOD: Those reporter constructs were used to evaluate the expression in response to cytokines and hormones. Deletion analysis of 1.8 kb fragment of ICAM-1 promoter in FRTL-5 cells provide the evidence for the existence of several regulatory elements of enhancer and silencer in ICAM-1 gene transcription in thyroid cells. RESULTS: ICAM-1 mRNA is easily detected by Northern analysis using total RNA from FRTL-5 cells regardless of culture conditions. The transcripts of rat ICAM-1 showed single band of 2.6 kb in length. The FRT cells which was come from early FRTL cell culture did not show ICAM-1 mRNA with usual Northern analysis, We found differential regulation of ICAM-1 RNA level in different culture condition in FRTL-5 cells, The cells maintained at 3H (no hydrocortisone, no insulin, no TSH) condition showed the highest expression level compared to 4H, 5H, or 6H medium. Hydrocortisone markedly decreased the ICAM-1 RNA and insulin partially recovered the hydrocortisone induced repression. TSH which is important in growth and function of FRTL-5 cells could independently downregulate the ICAM-1 RNA levels. Forskolin (10 mM) could mimic the action of TSH on ICAM-1 mRNA. TNF-a and interferon-y increase ICAM-1 expression in FRTL-5 thyroid cells. TSH/forskolin inhibited maximal expression of ICAM-1 by TNF-a and interferon-r. Promoter activity of the ICAM-1 gene was positively regulated by cytokines, TNF-a and IFN-r and negatively regulated by thyroid stimulating hormone. The addition of TSH and FSK caused a 50% decrease in ICAM-1 promoter activity within 24 hour. The TSH and FSK action was mapped at 175 bp and 97 bp of the start of translation. The mutant construct pCAM-175 delGAS which has no GAS sequence showed no TSH mediated suppression of promoter activity. CONCLUSION: These findings suggested that hormones and cytokines differentially regulated the ICAM-1 gene expression and TSH downregulated ICAM-1 gene transcription by inhibiting the activation of IFN-r induced transcription factors which can bind the GAS of ICAM-1 promoter.

The Induction of Apoptosis by Fas Antibody, IFN - delta, IL - 1 alpha in Normal Human Keratinocytes and KB cells / 대한피부과학회지

BACKGROUND: The Fas antigen is a cell surface molecule that mediates apoptosis in many cell types. Matsues group indicated that keratinocytes constitutively express the Fas antigen and apoptosis was induced only on pretreatment with interferon-r (IFN-y) in cultured normal human keratinocytes (NHK). OBJECTIVE: We undertook this study to determine the induction of apoptosis by Fas antibody alone and/or in combination with IFN y, IL-1a in normal human keratinocytes (NHK) and transitional epithelioma cell lines (KB cell) which had lower levels of intracellular IL-1 receptor antago- nists (IL-1ra ). METHODS: We used cultured NHK and KB cells. Each cell was treated with IFN-r, IL-la and Fas antibody for induction of apoptosis. For quantifying the apoptosis, index fluorescent DNA- binding dyes were used. Result: Fas antibody alone could induce apoptosis not only in KB cells but also in NHK cells. The combination of Fas antibody and IFN-r enhanced the induction of apoptosis in NHK and KB cells. The IL-la alone could induce apoptosis only in KB cells which had relatively small amounts of IL-1ra compared to NHK. CONCLUSION: Our result may indicate that Fas antigen in human keratinocytes can regulate normal epidermal cellular differentiation and proliferation.

Effect of Fibronectin to Macrophage for Destruction of MBT-2 Cell / 대한비뇨기과학회지

Fibronectin(Fn) is a large, multidomain glycoprotein, which exists in a soluble form in plasma and an insoluble fibrillar form in extracellular matrices. Fn affects many aspects of cellular responses. However, it is not known whether Fn could activate macrophages for the tumor cell killing. We report that Fn induces the tumoricidal activity of macrophages for murine bladder tumor(MBT-2) cell. Tumoricidal activity was determined by 3[H]-thymidine uptake of MBT-2 cell. Fn alone had no effect, whereas recombinant interferon- r(IFN- r) weakly induced the tumoricidal activity of macrophages for MBT-2 cells. However combination of Fn with recombinant IFN-r synergized to activate macrophages to kill MBT-2 cells in a dose dependent manner. At this point nitric oxide(NO) was secreted by activated macrophages, and the secretion of NO and tumoricidal activity of macrophage were inhibited in the presence of NG-monomethyl- L-arginine(NGMMA), a competitive inhibitor of NO synthase(NOS). Fn has various cell binding sites. The Arg-Gly-Asp(RGD) sequence present in the central cell binding domain of Fn is the prototype of these sites. Engineered fibronectin(eFn) is formed by RGD-rich sequence. Combination of eFn, instead of Fn, with recombinant IFN- T resulted in more powerful activation of macrophage in tumor cell killing than Fn. In conclusion, our results demonstrate that Fn acts as a modulator of macrophage activation for tumor cell killing induced by IFN-r via a process involving L-arginine dependent NO production. Especially, RGD sequence of Fn has important role for tumoricidal activity of macrophage. Although the precise mechanism of Fn to promote NO synthesis induced by IFN-r remains to be further elucidated, Fn-mediated macrophage adhesion by specialized cell surface receptors and activation of intracellular signals might be important in the development of macrophage activation.