Urocanic acid enhances IL-10 production in activated CD4+ T cells.
The immunosuppressive effects of UV radiation have been well documented. This suppression has been attributed to the action of the cis form of urocanic acid (UCA), a photoproduct of trans-UCA, a natural constituent of the skin. Here, we show that mouse spleen cells preincubated with cis-UCA have a diminished proliferative response to allogeneic cells in MLC and to stimulation with anti-CD3 mAb. Cells preincubated with cis-UCA also had a decreased ability to serve as APC and to stimulate the proliferation of allogeneic lymphocytes in MLC. Simultaneously, the production of IL-2 and IFN-gamma by cells preincubated with cis-UCA was decreased. However, IL-10 gene expression and IL-10 protein secretion by spleen cells stimulated in the presence of cis-UCA were significantly enhanced. The principal cell population displaying the cis-UCA-induced elevated production of IL-10 was CD4+ T cells, which were shown to be a direct target of cis-UCA action. This was also supported by the observation that production of IL-10 by stimulated splenic non-T cells or by macrophages was not altered by cis-UCA. The enhanced production of IL-10 by activated CD4+ T cells may represent a novel pathway of UVB radiation-induced, cis-UCA-mediated immunosuppression. We suggest that the elevated production of IL-10 by activated CD4+ T cells may account for the suppressor T cell phenomena described in UV-irradiated recipients.
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague. holan@img.cas.cz
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Holán
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L
Kuffová
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Zajícová
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M
Krulová
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Filipec
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Holler
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Jancárek
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D017951:Antigen Presentation / Q000187:drug effects; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013237:Stereoisomerism; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000378:metabolism; D014560:Urocanic Acid / Q000494:pharmacology*
D000276:Adjuvants, Immunologic; D016753:Interleukin-10; D014560:Urocanic Acid