Clinical and immunobiochemical characterization of airborne Delonix regia (Gulmohar tree) pollen and cross-reactivity studies with Peltophorum pterocarpum pollen: 2 dominant avenue trees from eastern India.
BACKGROUND
Delonix regia and Peltophorum pterocarpum pollen are important aeroallergens for type 1 hypersensitivity in the tropics. The IgE-binding proteins of D regia and their cross-allergenity with P pterocarpum pollen have not been evaluated.


OBJECTIVE
To isolate and characterize the IgE-binding proteins of D regia pollen for the first time and to investigate the cross-allergenity with P pterocarpum pollen belonging to the same family (Leguminosae).


METHODS
Allergenic activities were determined by in vivo and in vitro analyses. Pollen extract was fractionated by a combination of 2 columns (diethyl amino ethyl Sephadex and Sephacryl S-200). Protein components were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, periodic acid-Schiff staining, and immunoblotting. In vitro inhibition tests were performed to evaluate the cross-reactivity.


RESULTS
The skin prick test results of the patients with respiratory allergies in Calcutta, India, showed 31.1% positivity with D regia pollen. Nine IgE-reactive protein components were found in the crude extract. An optimum IgE-reactive fraction was resolved into 4 subfractions. Subfraction A, which showed maximum IgE reactivity, contained 2 (96- and 66-kDa) IgE-reactive protein components. The 66-kDa component was found to be glycoprotein. Remarkable cross-reactivity between D regia and P pterocarpum pollen was found on IgE enzyme-linked immunosorbent assay inhibition and dot blotting. Shared IgE-binding components (66, 56, 32, 28, 25, and 23 kDa) were observed between D regia and P pterocarpum pollen extracts, whereas the 96- and 43-kDa components were specific to D regia.


CONCLUSIONS
The purification of the IgE-binding proteins and the identification of the shared/cross-reactive proteins in these taxonomically related pollen members should be helpful for the diagnosis and therapy of patients susceptible to these pollens.
Mandal
Jyotshna
J
Division of Palynology and Environmental Biology, Department of Botany, Bose Institute, Calcutta, India.
Manna
Prasenjit
P
Chakraborty
Pampa
P
Roy
Indrani
I
Gupta-Bhattacharya
Swati
S
D000293:Adolescent; D000328:Adult; D052179:Antigens, Plant / Q000032:analysis / Q000276:immunology; D001249:Asthma / Q000276:immunology / Q000503:physiopathology; D001667:Binding, Competitive / Q000276:immunology; D015153:Blotting, Western; D003429:Cross Reactions / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D007887:Fabaceae / Q000276:immunology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006023:Glycoproteins / Q000032:analysis / Q000276:immunology; D006636:Histamine Release / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000276:immunology; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007194:India; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000737:chemistry / Q000276:immunology; D010940:Plant Proteins / Q000032:analysis / Q000276:immunology; D011058:Pollen / Q000737:chemistry / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000276:immunology* / Q000503:physiopathology; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000503:physiopathology; D012882:Skin Tests; D014197:Trees / Q000276:immunology*; D055815:Young Adult
D052179:Antigens, Plant; D006023:Glycoproteins; D010936:Plant Extracts; D010940:Plant Proteins; D007073:Immunoglobulin E