Mobile IPv6에서 효율적인 동적 페이징 방식

Abstract

Background: Rhinovirus (RV) is a well-known cause of upper respiratory tract infections and an important trigger of asthmatic exacerbation. RV can augment tissue eosino philia when combined with antigen in appropriately sensi. tized patients. RANTES, a subfamily of chemokines with double cysteine motif, is a potent eosinophil chemoattractant. Objective: This study was designed to investigate RV stim ulation of RANTES and NF-kB-dependent transcriptional mechanism in alveolar epithelial cells in vitro. Method: After RV14 infecion on A549 cells, RANTES protein and mRNA were measured using ELISA and RTPCR. To further understand the transcriptional mechanisms of RANTES production, NF-kB activity was checked with gel shift assay including supershift and competition assay. The mechanism of RANTES promoter activation was analyzed by cis-element assay with mutagenesis experiment. NF-KB activity was inhibited with antioxidant, TLCK, TPCK, and mutant I KB a Result: RANTES and mRNA levels were increased and peaked at 12 hours after infection with RV14. RV also stimulated NF-KB-DNA binding activity. Supershift assays revealed that this binding was due to p65 and, to a lesser extent, p50 NF-kB subunits. Cis-element analysis of RANTES promoter showed that NF-kB binding site between -50 and -40 was the most important region. A dominant negative mutant of IxBa abrogated RV-induced RANTES promoter activity. Selective antioxidants, N-acetylcysteine, and NF-K B blockers (TLCK, TPCK) inhibited RV-stimulated RANTES production and promoter activity in alveolar epithelial cells. Conclusion: RV is a potent stimulator of RANTES production in A549 cells in vitro. This inductive effect is, to a great extent, transcriptionally mediated and dependent on NF-kB activation. The most important subuinits of NF-KB are p65/p50, which are interacted with RNATES promoter site between -50 and -40. RANTES production, are inhibited by antioxidant and NF-kB blockers.