Antigen-specific tolerance induced by IL-10 gene modified immature dendritic cells in experimental autoimmune myocarditis in rats.
BACKGROUND
Experimental autoimmune myocarditis (EAM) in rats is a T-cell-mediated disorder. The initiation and maintenance of autoimmune responses in EAM depend on the maturation state of dendritic cells. IL-10 is a pleiotrophic immunomodulatory cytokine that functions at different levels of the immune response, so it has emerged as a promising therapeutic factor for the treatment of autoimmune/inflammatory diseases. This study was designed to test the hypothesis that IL-10 gene modified bone marrow-derived immature dendritic cells (iDCs) ameliorate EAM and to explore the underlying mechanisms.


METHODS
EAM was induced using the methods of cardiac myosin immunization on day 0 and day 7. Immature and mature bone marrow-derived dendritic cells (BMDCs) were generated without or with the stimulation by lipopolysaccharide (LPS) and the phenotype was analyzed by flow cytometry. Some of the iDCs were transfected by pcDNA3-IL-10 plasmid. 2 x 10(6)/per rat mature DC (mDC), immature DC (iDC), pcDNA3 transfected iDC, pcDNA3-IL-10 transfected iDC or phosphate buffered saline (PBS) were injected intravenously for treatment 5 days after the first immunization. On day 21, HE staining was performed to detect the myocardial inflammation and T lymphocyte proliferation assay was used to determine the effects of IL-10 gene transfected iDC on autoreactive T cell proliferation. Expression of IkappaB, the inhibitor of NF-kappaB pathway, was determined by Western blot.


RESULTS
BMDCs generated in a medium supplemented with granulocyte-macrophage-colony-stimulating factor (GM-CSF) were relatively immature, as determined by flow cytometry. However, stimulation with LPS induced these cells to become mature (m) DCs with higher levels of surface major histocompatibility complex (MHC)-II and costimulatory molecules. Intravenous administration of iDCs, especially pcDNA3-IL-10 transfected iDC, ameliorated the histopathological severity of the myosin induced-EAM, and the effect was lost after the DCs underwent maturation induced by in vitro exposure to LPS. IL-10 gene modified iDC inhibited the antigen specific T cell responses towards cardiac myosin. IkappaB protein was up-regulated significantly in the IL-10 gene modified iDC group.


CONCLUSIONS
IL-10 gene modified iDC induced antigen-specific tolerance in EAM. The underlying mechanisms may be related to costimulatory molecules down-regulation and NF-kappaB pathway inhibition.
Li
Wei-min
WM
Department of Cardiology, First Affiliated Hospital, Harbin Medical University, Harbin 150001, China. dr_liweimin@yahoo.com.cn
Liu
Wei
W
Gao
Cheng
C
Zhou
Bao-guo
BG
Yang
Shu-sen
SS
Wang
Zheng
Z
Zhang
Rui-hong
RH
Gan
Run-tao
RT
Kong
Yi-hui
YH
Li
Yue
Y
D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology*; D003713:Dendritic Cells / Q000502:physiology*; D007108:Immune Tolerance; D016753:Interleukin-10 / Q000235:genetics*; D008213:Lymphocyte Activation; D008297:Male; D009205:Myocarditis / Q000276:immunology*; D009218:Myosins / Q000276:immunology*; D016328:NF-kappa B / Q000502:physiology; D051381:Rats; D011917:Rats, Inbred Lew; D015398:Signal Transduction; D014162:Transfection
D016328:NF-kappa B; D016753:Interleukin-10; D009218:Myosins