NF-κB and TNF-α: a positive autocrine loop in human lung mast cells?
Coward, William R., Okayama, Yoshimichi, Sagara, Hironori, Wilson, Susan J., Holgate, Stephen T. and Church, Martin K. (2002) NF-κB and TNF-α: a positive autocrine loop in human lung mast cells? Journal of Immunology, 169, (9), 5287-5293.
The generation of cytokines, particularly TNFα-, by mast cells is crucial for the initiation of the allergic response. A key transcription factor involved in the synthesis of TNFα- is NFκ-B. Using a mAb specific for the activated form of NFκ-B, immunocytochemistry, confocal microscopy, and gel shift assays have been used in conjunction to localize this transcription factor to human lung mast cells and to study its activation. Activation of mast cells with stem cell factor (10 ng/ml) and anti-IgE (1 µg/ml) induced maximal activation of NFκ-B at 4 and 2 h, respectively. In contrast, with TNFα- (5 ng/ml) maximal activation occurred within 15 min.
Parallel falls in IB were demonstrated. Confocal microscopy demonstrated the localization of the activated form of NFκ-B to the nuclei of activated mast cells. NFκ-B activation was verified using a gel shift assay. A supershift assay showed mast cell NF-B to be composed primarily of p50 with smaller amounts of p65. No interaction with Abs for Rel-A, c-Rel, Rel-B, and p52 was seen. Immunocytochemistry and ELISAs showed TNFα- to be stored within mast cells and released into the extracellular environment following activation. The possible participation of TNFα- generated by mast cells in NFκ-B activation by anti-IgE was investigated using a blocking Ab for TNFα-. The blocking Ab reduced NFκ-B activation by anti-IgE by >50%, suggesting that the release of preformed mast cell-associated TNFα- acts as a positive autocrine feedback signal to augment NFκ-B activation and production of further cytokine, including GM-CSF and IL-8.
|Subjects:||Q Science > QR Microbiology > QR180 Immunology
Q Science > QP Physiology
|Divisions:||University Structure - Pre August 2011 > School of Medicine > Infection, Inflammation and Repair
|Date Deposited:||26 Apr 2006|
|Last Modified:||27 Mar 2014 18:15|
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