title: Effect of pollen-mediated oxidative stress on immediate hypersensitivity reactions and late-phase inflammation in allergic conjunctivitis.
abstract: BACKGROUND
  Allergic eye diseases are complex inflammatory conditions of the conjunctiva that are becoming increasingly prevalent and present an increasing economic burden because of direct and indirect health expenditures.
  
  
  OBJECTIVE
  We sought to identify factors that may synergize with antigen-induced allergic inflammation and lead to allergic conjunctivitis. We used a murine model of allergic conjunctivitis to test the effect of oxidative stress generated by pollen oxidases using nicotinamide adenine dinucleotide (reduced) or nicotinamide adenine dinucleotide phosphate (reduced) (NAD[P]H) as an electron donor present in pollen grains.
  
  
  METHODS
  Reactive oxygen species (ROS) generation by hydrated Ambrosia artemisiifolia pollen (short ragweed pollen; RWP) grains was determined by using 2'-7'-dihydro-dichlorofluorescein diacetate, nitroblue tetrazolium reduction, and Amplex Red assay. The RWP-induced changes in intracellular ROS levels were examined in A549 cells, human primary bronchial epithelial cells, and murine conjunctiva.
  
  
  RESULTS
  Ragweed pollen grains contain NAD(P)H oxidase activity, which is diphenyleneiodonium-sensitive and quinacrine-sensitive and sodium azide-resistant. These NAD(P)H oxidases generate a superoxide anion that can be converted to H2O2 by pollen grain-associated superoxide dismutase. These diffusible oxygen radicals from pollen grains increase intracellular ROS levels in cultured epithelial cells and murine conjunctiva. Similar phenomena were observed in sensitized and naive mice, indicating that the RWP-induced oxidative stress in conjunctival epithelium is independent of adaptive immunity. Inactivation of NAD(P)H oxidase activity in RWP decreases the immediate-type hypersensitivity and inflammatory cell infiltration into the conjunctiva.
  
  
  CONCLUSIONS
  Our data suggest that ROS generated by NAD(P)H oxidases in pollen grains intensify immediate allergic reactions and recruitment of inflammatory cells in murine conjunctiva.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
authors.forename: Attila
authors.initials: A
authors.lastname: Bacsi
authors.forename: Nilesh
authors.initials: N
authors.lastname: Dharajiya
authors.forename: Barun K
authors.initials: BK
authors.lastname: Choudhury
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Sur
authors.forename: Istvan
authors.initials: I
authors.lastname: Boldogh
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003233:Conjunctivitis, Allergic / Q000209:etiology / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D018384:Oxidative Stress; D011058:Pollen / Q000276:immunology* / Q000378:metabolism* / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D009243:NAD; D009249:NADP; D009247:NADH, NADPH Oxidoreductases