Allergenic potential of rice-pollen proteins: expression, immuno-cross reactivity and IgE-binding

J Biochem. 2013 Aug;154(2):195-205. doi: 10.1093/jb/mvt044. Epub 2013 May 20.


Pollen proteins from several grass species have been identified and characterized as causative allergens in grass pollinosis. In contrast, allergenic potential of pollen proteins from rice, which belongs to the same Poaceae family, has not well been investigated, despite that a few clinical cases have been reported on rice-pollen allergy. In this study, to characterize expression and allergenic potential of pollen proteins from rice (Oryza sativa, ssp. japonica), rice putative proteins for β-expansin (EXP), a Ca(2+)-binding protein (CBP)/polcalcin, extensin (EXT), profilin (PRF) and polygalacturonase (PGA) retrieved from a rice complete cDNA database were prepared as recombinant proteins, and the antibodies to these recombinant proteins were obtained. Immuno-blotting and immuno-histological analyses showed that rice putative EXP, EXT and PGA were expressed abundantly in anther tissue and pollen granules and immuno-cross reactive with pollen proteins from timothy grass. ELISA and immuno-dot blotting analyses using serum specimens from allergic patients showed that majority of the specimens was positive in the IgE-binding to EXP and EXT, but weakly to PGA and almost negative to PRF. EXP and EXT were suggested to be potentially allergenic in the rice-pollen allergy as well as the grass pollinosis.

Keywords: allergen; extension; grass pollinosis; rice pollen; β-expansin.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Allergens / chemistry
  • Allergens / genetics
  • Allergens / immunology*
  • Antibody Specificity
  • Binding Sites, Antibody
  • Child
  • Child, Preschool
  • Cross Reactions
  • Escherichia coli / genetics
  • Female
  • Gene Expression
  • Humans
  • Immunoglobulin E / immunology*
  • Infant
  • Male
  • Oryza / chemistry
  • Oryza / genetics
  • Oryza / immunology*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / immunology*
  • Pollen / chemistry
  • Pollen / genetics
  • Pollen / immunology*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Rhinitis, Allergic, Seasonal / immunology*


  • Allergens
  • Plant Proteins
  • Recombinant Proteins
  • Immunoglobulin E