Inhibition of Interleukin-1 Signal by Annexin-1 in Phorbol Myristate Acetate Stimulated Lymphocytes / 대한면역학회지

Annexin-1 (ANX1) is a 37 kDa protein that is induced and secreted by glucocorticosteroid hormone. The secreted ANX1 has been believed to exert its function by binding to its putative rnembrane receptor. In this report we demonstrate that ANXl receptor (ANX1R) signal blocks the interleukin-1B (IL-1B) receptor signal pathway in human peripheral blood mononuclear cells (PBMCs). When PBMCs were treated with both IL-1B (100 ng/ml) and PMA (10 ng/ml) in the absence or presence of dexamethasone for 5 days, dexamethasone (100 nM) suppressed lymphocyte proliferation to 24% of the control. However addition of anti-ANX1 polyclonal antibody of 1:200 and 1:1,000 dilution to this system induced recovery of proliferation to 80% and 40%, respectively, when compared to the control. In the mixed lymphocyte reaction, dexamethasone suppressed lymphocyte proliferation to 9% of that of control when stimulated with IL-1B (100 ng/ml) and phorbol myristate acetate (10 ng/ml). Addition of anti-ANX1 polyclonal antibody (1:1,000) to this system also recovered the proliferation to 20% of that of the control system. In the ANX1 receptor induction experiment using flow cytometry, ANX1 receptor expression on lymphocytes, CD4+ T cells, CD8+ T cells and monocytes increased depending on the externally added IL-1B ranging from 10 to 1,000 ng/ml. From these results, it is evident that dexamethasone induces ANX1 secretion into the culture medium and anti-ANX1 polyclonal antibody abolishes the effects of dexamethasone. Furthermore these results imply that extracellular ANX1 exerts its effects by binding to the receptor on the cell membrane and the activated signal(s) of ANX1R block IL-1B receptor signal in the lymphocytes.

Hepatitis C virus genotyping of 100 consecutive anti-HCV positive cases with PCR using type=specific primers / 대한간학회지

BACKGROUND/AIMS: The distribut ion of HCV genotypes varies with geographical area, and genot ypes can affect t he nat ur al course of HCV infection, but adequate genot yping data were not accumulat ed in Korea. This study was des igned to det ermine the pattern of distribution of HCV genotypes in Korea and it's clinical implications. METHODS: 100 cons ecut ive anti- HCV( +), RT-PCR(+) cases were recruited. Genotype specific oligonucleotide primers were made according to the sequence variation of NS5 region of HCV genome. Heminested PCR with mixed primersets was per formed, and genotype specific PCR products of different size were verified. Sequencing of cloned PCR products was done in cases with representative genotypes. Clinical profiles of genotype 1b and 2a were compared. RESULTS: Genotyping was done in 78 among 100 cases. Genotype 1b (48/ 78, 57.7%) and 2a (25/ 78, 32.1%) were most prevalent , and 1a (1/ 78, 1.3%) and mixed form (7/ 78, 9.0%) were also found. Milder cases with persistent normal ALT levels were more frequently seen in genotype 2a ( 9/ 25, 36.0%) than in genot ype 1b (3/ 45, 6.7%) (p< 0.01). CONCLUSIONS: Genotype 1b and 2a were major ones in anti- HCV( +) Korean adults, and the tendency of milder clinical course of genotype 2a was suggested.

Lipocortin 1 mediates the suppressive effects of dexamethasone on CoNinduced proliferative response and nitric oxide production in rat splenic leukocytes

Lipocortin 1 has been proposed as a putative mediator of anti-inflammatory actions of glucocorticoids. We investigated the role of lipocortin 1 in the effect of dexamethasone using rat splenic leukocytes. Concanavalin A(ConA; 1-microgram/ml) increased the leukocyte proliferation and nitric oxide(NO) generation, which were measured as (3H)-thymidine uptake by the cells and nitrite accumulation in the culture media, respectively. Dexamethasone suppressed CoNinduced cell proliferation, in a concentration-dependent manner with EC-50 around 50nM. The addition of anti-lipocortin 1 (Anti-LC1) reversed dexamethasone effects: 0.24, 1.2, 6 microgram/ml of Anti-LC1 reversed dexamethasone(50nM)-induced suppression of thymidine uptake by 9+/-3%, 16+/-3%, 36+/-5%, respectively; 0.24, 1.2, and 6-microgram/ml of Anti-LC1 reversed dexamethasone-induced decrease of nitrite concentration by 49 +/- 16%, 61 +/- 20%, 77 +/- 19 %, respectively. The present data indicate that lipocortin 1 mediates, at least in part, glucocorticoids-induced suppression of leukocyte proliferation and blockade of NO generation.