Secondary Logo

Journal Logo

Institutional members access full text with Ovid®

Role of pollen NAD(P)H oxidase in allergic inflammation

Dharajiya, Nilesh; Boldogh, Istvan; Cardenas, Victor; Sur, Sanjiv

Current Opinion in Allergy and Clinical Immunology: February 2008 - Volume 8 - Issue 1 - p 57–62
doi: 10.1097/ACI.0b013e3282f3b5dc
Mechanisms of allergy and adult asthma: Edited by Stephen T. Holgate and J. Andrew Grant

Purpose of review Plant pollens are one of the most common outdoor allergens. Pollen grains and subpollen particles can reach lower airways and induce symptoms of seasonal asthma and allergic rhinitis. Plants possess NAD(P)H oxidase activity that generates reactive oxygen species for physiological functions such as root-hair and pollen-tube growth, defense against microbial infections and cell signaling. The presence of NAD(P)H oxidases in pollens and their role in induction of airway inflammation have not been described until recently.

Recent findings We discovered the presence of NAD(P)H oxidase in ragweed and other plant pollens. These oxidases induce reactive oxygen species in mucosal cells (signal 1) independent of adaptive immunity. This reactive oxygen species facilitates antigen (signal 2)-induced allergic inflammation. Inhibiting signal 1 by administration of antioxidants attenuated ragweed extract-induced allergic inflammation. Likewise, abrogating signal 2 by antigen challenge in mice lacking T cells failed to induce allergic inflammation.

Summary Reactive oxygen species generated by pollen NAD(P)H oxidase play a major role in pathogenesis of allergic airway inflammation and airway hypersensitivity. Based on our findings, we propose a ‘two signal hypothesis of allergic inflammation’ in which both signal 1 (reactive oxygen species) and signal 2 (antigen presentation) are required in order to induce full-blown allergic inflammation.

aNHLBI Proteomics Center, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA

bDepartment of Microbiology and Immunology, Sealy Center for Molecular Medicine, University of Texas Medical Branch, Texas, USA

cDivision of Allergy Pulmonary Immunology Critical Care and Sleep, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA

Correspondence to Sanjiv Sur, MD, Divisions of Allergy Pulmonary Immunology Critical Care and Sleep, Departments of Internal Medicine, Microbiology & Immunology, Biochemistry & Molecular Biology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1083, USA Tel: +1 409 772 3410; e-mail:

Copyright © 2008 Wolters Kluwer Health, Inc. All rights reserved.