title: Suppression of experimental autoimmune encephalomyelitis by ultraviolet light is not mediated by isomerization of urocanic acid.
abstract: Ultraviolet B irradiation confers strong resistance against experimental autoimmune encephalomyelitis, a model of multiple sclerosis. This protection by ultraviolet B is independent of vitamin D production but causes isomerization of urocanic acid, a naturally occurring immunosuppressant.
  
  
  
  To determine whether UCA isomerization from trans to cis is responsible for the protection against experimental autoimmune encephalomyelitis afforded by ultraviolet B, trans- or cis-urocanic acid was administered to animals and their disease progression was monitored.
  
  
  
  Disease incidence was reduced by 74% in animals exposed to ultraviolet B, and skin cis-urocanic acid levels increased greater than 30%. However, increasing skin cis-urocanic acid levels independent of ultraviolet B was unable to alter disease onset or progression.
  
  
  
  It is unlikely that urocanic acid isomerization is responsible for the ultraviolet B-mediated suppression of experimental autoimmune encephalomyelitis. Additional work is needed to investigate alternative mechanisms by which UVB suppresses disease.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706, USA.
authors.forename: Amy A
authors.initials: AA
authors.lastname: Irving
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Marling
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706, USA.
authors.forename: Lori A
authors.initials: LA
authors.lastname: Plum
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI, 53706, USA. deluca@biochem.wisc.edu.
authors.forename: Hector F
authors.initials: HF
authors.lastname: DeLuca
mesh_terms: D000818:Animals; D018450:Disease Progression; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000378:metabolism* / Q000628:therapy; D005260:Female; D007536:Isomerism; D051379:Mice; D008810:Mice, Inbred C57BL; D009103:Multiple Sclerosis / Q000378:metabolism* / Q000628:therapy; D014466:Ultraviolet Rays; D014467:Ultraviolet Therapy; D014560:Urocanic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D014560:Urocanic Acid