IFN-alpha Downregulates ERK Phosphorylation of CD4+ T Lymphocytes in Systemic Lupus Erythematosus.
- Author:
Wan Hee YOO
1
Author Information
1. Department of Internal Medicine, Chonbuk National University Medical School, Research Institute of Clinical Medicine, Jeonju, Korea. ywhim@chonbuk.ac.kr
- Publication Type:Original Article
- Keywords:
CD4+ T cells;
ERK signal;
IFN-alpha;
Systemic lupus erythematosus
- MeSH:
Culture Media;
Enzyme-Linked Immunosorbent Assay;
Flow Cytometry;
Humans;
Lupus Erythematosus, Systemic*;
Phosphorylation*;
Plasma;
T-Lymphocytes*
- From:The Journal of the Korean Rheumatism Association
2006;13(3):193-202
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
OBJECTIVE: CD4+ T cells from patients with systemic lupus erythematosus (SLE) display aberrant TCR signaling and IFN-alpha plays critical roles in the pathogenesis of SLE; however, the effects of IFN-alpha on disease-associated TCR signaling defects remain unknown. This study investigated the ERK phosphorylation during TCR triggering and the effects of IFN-alpha on ERK signaling in CD4+ T cells. METHODS: CD4+ T lymphocytes were sorted from PBMC using magnetic beads in patients with SLE who met the 1982 revised ACR criteria for SLE and age-matched healthy controls. The phosphorylation of ERK 1/2 was analyzed by flow cytometry and mean fluorescent intensity was measured to define the degree of phosphorylation of ERK. In some experiments, anti-CD3 stimulation was performed after preincubation with patient or control serum, diluted in tissue culture media, with or without addition of an anti-IFN-alpha antibody. The serum level of IFN-alpha was measured by ELISA. RESULTS: ERK-1/2 phosphorylation was decreased in CD4+ T cells of lupus patients than healthy controls and associated with disease activity. Pre-incubation of control CD4+ T cells with allogeneic lupus plasma decreased ERK-1/2 phosphorylation more than allogeneic control and RA plasma and this was reversed by anti-IFN-alpha Ab. Accordingly, ERK-1/2 phosphorylation was decreased in control CD4+ T cells pre-incubation with lupus plasma with high IFN-alpha levels more than lupus plasma with non-detectable IFN-alpha levels. Recombinant IFN-alpha inhibited TCR-mediated ERK-1/2 phosphorylation dose-dependently. CONCLUSION: These results suggest that IFN-alpha stimulation in vivo may underlie the aberrant TCR-mediated MAPK signaling in lupus CD4+ T cells and associated with disease pathogenesis.
