The major Platanus acerifolia pollen allergen Pla a 1 has sequence homology to invertase inhibitors

Clin Exp Allergy. 2003 Jul;33(7):978-85. doi: 10.1046/j.1365-2222.2003.01707.x.


Background: Sycamores or plane trees are an important source of airborne allergens in many cities of the United States and Western Europe. Pla a 1 has been described as a major allergen from Platanus acerifolia (London plane tree).

Objective: To clone and characterize the cDNA for Pla a 1 and to express the recombinant protein.

Methods: Pla a 1 was isolated by cationic exchange, gel filtration, and reverse-phase chromato-graphies. Pla a 1 cDNA was cloned by reverse transcription followed by polymerase chain reaction, using amino acid sequences from tryptic peptides of the allergen. The Pla a 1 encoding sequence has been subcloned into the pKN172 expression vector and expressed in Escherichia coli as a non-fusion protein. Purified recombinant protein has been tested for its IgE-binding capacity in immunoblot, immunoblot inhibition, and ELISA.

Results: Pla a 1 reacted with serum IgE from 35 of the 42 (83.3%) Platanus-allergic patients studied and represented 60% of the total IgE-binding capacity of the P. acerifolia pollen extract. The allergen displayed 43% sequence identity to a grape invertase inhibitor and showed a predicted secondary structure characteristic of all-alpha proteins. Serological analysis revealed that both natural and recombinant forms of Pla a 1 displayed similar IgE-binding capacity.

Conclusions: Pla a 1 belongs to a new class of allergens related to proteinaceous invertase inhibitors. Recombinant Pla a 1 binds IgE in vitro like its natural counterpart and, therefore, it can be useful for specific diagnosis and structural studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aceraceae
  • Allergens / genetics*
  • Antigens, Plant
  • Cloning, Molecular
  • DNA, Complementary / genetics*
  • Humans
  • Plant Extracts / genetics*
  • Pollen / genetics*
  • Polymerase Chain Reaction
  • RNA, Messenger / genetics
  • Sequence Homology, Amino Acid*
  • Sequence Homology, Nucleic Acid*
  • Trees
  • beta-Fructofuranosidase / antagonists & inhibitors
  • beta-Fructofuranosidase / genetics*


  • Allergens
  • Antigens, Plant
  • DNA, Complementary
  • Pla a 1, Platanus acerifolia
  • Plant Extracts
  • RNA, Messenger
  • beta-Fructofuranosidase