| Autor: |
Yi AK; Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242, USA., Chace JH, Cowdery JS, Krieg AM |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of immunology (Baltimore, Md. : 1950) [J Immunol] 1996 Jan 15; Vol. 156 (2), pp. 558-64. |
| Abstrakt: |
Lymphocyte recognition of characteristic structural features in microbial DNA may contribute to immune defense by promoting protective immune responses. The dinucleotide CpG is significantly under-represented in vertebrate DNA and is usually methylated. In contrast, CpG dinucleotides are generally present at the expected frequency in bacterial DNA and are unmethylated. These unmethylated CpG motifs induce B cells to secrete IL-6 and IgM, and can induce NK and CD4+ T cells to produce the immunoregulatory Th1 cytokine, IFN-gamma. IFN-gamma inhibits IgM secretion that is triggered by a different bacterial product, LPS. The present study demonstrates that in contrast to its antagonistic interaction with LPS, IFN-gamma causes a dose-dependent increase in the level of IgM secretion induced by CpG DNA. Like IgM secretion, B cell secretion of IL-6 more than doubles after the addition of exogenous IFN-gamma. Mice with disrupted IFN-gamma genes produced less than half as much IL-6 and IgM in response to CpG DNA, supporting the hypothesis that CpG-induced IFN-gamma production contributes to the B cell response. In contrast to its promotion of IL-6 and IgM secretion, IFN-gamma did not significantly affect the spleen cell proliferation activated by CpG motifs. These results indicate that IFN-gamma produced by T and NK cells after CpG DNA stimulation contributes to the B cell production of IL-6 and the subsequent Ig production. These studies provide further evidence that the immune system responds to CpG motifs in bacterial DNA by activating a coordinated set of humoral and cellular responses. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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