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말초혈액 단핵구와 단핵구 유래 세포주 THP1에서 FcrR 자극에 의해 유도되는 염증반응의 조절기전
윤강순,윤석란,이충은,김형순,변광호 大韓免疫學會 1993 大韓免疫學會誌 Vol.15 No.-
Regulation mechanisms of inflammatory responses induced by FcrR stimulation in human monocytes and monocytic cell line THP1 were investigated. Release of arachidonic acid, which is the precusor for inflammatory mediators, was induced by FcrR stimulation with its ligand human IgG or with anti FcrR mAbs. This response was further increased when FcrR was cross-linked with in-soluble anti-IgG-agarose and soluble anti-IgG Fc specific Fab fragments. These phenomena were shown in both monocyte and THP1. Oxidative burst activity, resulting from generation of reactive oxygen speices, was also induced by FcrR stimulation and further enhanced by cross-linking of Fcr R. Induction mechanisms of inflammatory responses caused by PMA or FcrR stimulations were then examined by measurements of release of arachidonic acid and oxidative burst activity. The results demonstrate that monocytes utilize different signaling pathways for FcrR or PMA stimulation. Signaling mechanism of PMA stimulation is especially dependent on Ca}+/calmodulin dependent kinase in arachidonic acid release, but not in oxidative burst activity. Meanwhile, signaling pathways of FcrR are dependent on tyrosine kinase but independent of protein kinase C both in the release of arachidonic acid and oxidative burst activity. The results suggest that in monocytes, there is a not only functional but also mechanistic link between arachidonic acid release and oxidative burst activity induced upon FcrR stimulation. Distinct signaling pathways seem to be operating in transformed monocytic cell line THP-1 cells, and no mechanistic link was found between arachidonic acid release and oxidative burst activity induced after FcrR stimulation.
B 림프구 활성화 자극에 따른 Interleukin-4 수용체와 Type II IgE 수용체 발현조절양상의 상호관련성
이충은,윤석란,변광호,소의영 大韓免疫學會 1995 大韓免疫學會誌 Vol.17 No.3
Interleukin-4(IL-4) specifically induces the expression of its own receptor, IL-4R and type II IgE receptor, FceR1l in a dose-dependent manner in human B lymphocytes. We observed that the IL-4-induced expression of IL-4R and Fce Rll were both down-regulated by interferon-T(IFN-T) at mRNA as well as surface protein levels in normal B lymphocytes. Such co-ordinated regulation of the IL-4-induced IL-4R and FceRlI also occurred by anti-CD40 and steroid, each regulating the IL-4-induced response in an opposite direction. While anti-CD40, which is re-ported to agument the IL-4-induced B cell activation, further enhanced the IL-4-induced IL-4R and Fee RU expression, methylprednisolon(MPD) strongly inhibited the level of these receptors. The anti-CD40 or MPD-induced modulation of the IL-4-induced IL-4R and FceRII was further subject to the down-regulation by lFN-T. As compared to normal B lymphocytes, a differential regulation of IL-4R and FceRII was noted in a transformed B cell line, where IFN- Tup-regulated the IL-4-induced responses. Still, there was a co-ordinated regulation of the IL-4R and FceRII in these cells. Taken together, these results suggest that modulation of IL-4R expression and FccRII induction are closely correlated events during the IL-4-induced cellular activation
인체 B 림프구 활성화의 신호전달과정에서 IL-4 수용체와 CD40 분자간의 상호작용
이충은,윤석란,변광호 大韓免疫學會 1995 大韓免疫學會誌 Vol.17 No.3
Stimulation of B cells through CD40 antigen has been reported to agument the interleukin-4(IL-4)induced B cell proliferation and differentiation. In order to elucidate mechanisms underlying the synergistic action, we examined the effect of CD40-mediated signal on the IL-4-induced B cell activation. Treatment of dense, resting tonsillar B cells with agonistic anti-CD40 mAb caused a noticeable induction of IL-4 receptor(IL-4R) mRNA expression within hours, which was followed by a significant enhancement of the IL-4-induced surface IL-4R and CD23 expression, suggesting a role of CD40 in amplifying the IL-4-induced signal. Signal interplay between the IL-4 and the CD40 system was further supported by the observation that, in tonsillar B cells, IL-4 plus anti-IgM induced CD40 expression and tyrosine phosphorylation of IL-4R, and that anti-CD40 co-immunoprecipitated the IL-4R and the IL-4R associated tyrosine kinase activity, which implies a possible molecular interaction between IL-4R and CD40. Together these results suggest that there is a cross-talk between CD40-and the IL-4R-mediated signal transduction system during the T cell-dependent B cell activation.
Intracellular pH is a Critical Element in Apoptosis Triggered by GM-CSF Deprivation in TF1 Cells
Yoon, Suk Ran,Choi, In Pyo The Korean Association of Immunobiologists 2003 Immune Network Vol.3 No.4
Background: Hemopoietic cells require the constant presence of growth factors for survival in vitro and in vivo. Caspases have been known as central executors of apoptotic cell death. We have, therefore, investigated the pathways that regulate caspase activity and apoptosis using the $CD34^+$ cell line, TF-1 which requires GM-CSF for survival. Methods: Apoptosis was measured by annexin V staining and mitochondrial membrane potential was measured by DiOC6 labelling. Intracellular pH was measured using pH sensitive fluorochrome, BCECF or SNARF-1, followed by flow cytometry analysis. Caspase activation was analyzed by PARP cleavage using anti-PARP antibody. Results: Removal of GM-CSF induceed PARP cleavage, a hallmark of caspase activity, concomitant with pHi acidification and a drop in mitochondrial potential. Treatment with ZVAD, a competitive inhibitor of caspases, partially rescued cell death without affecting pHi acidification and the reduction of mitochondrial potential, suggesting that both these events act upstream of caspases. Overexpression of Bcl-2 prevented cell death induced by GM-CSF deprivation as well as pHi acidification and the reduction in mitochondrial membrane potential. In parental cells maintained with GM-CSF, EIPA, a competitive inhibitor of $Na^+/H^+$ antiporter induced apoptosis, accompanied by a drastic reduction in mitochondrial potential. In contrast, EIPA induced apoptosis in Bcl-2 transfectants without causing mitochondrial membrane depolarization. Conclusion: Taken together, our results suggest that the regulation of $H^+$fluxes, either through a mitochondriondependent or independent pathway, is central to caspase activation and apoptosis.