CLONING, SEQUENCING AND EXPRESSION IN Escherichia coli OF THE MAJOR ALLERGEN FROM ALDER (Alnus sieboldiana) POLLEN

Pollen of the alder (Alnus sieboldiana) is one of the main causes of Type Ⅰ allergies in Japan, especially in densely cultivated areas. cDNA clones coding for the major alder pollen allergen, Aln s 1, were isolated. The clones contained an open reading frame of 477 nucleotides. Comparison of the deduced amino acid sequence of Aln s 1 to the major allergens from Betulaceae pollen such as Aln g 1, Bet v 1, Cor a 1 and Car b 1 showed identities of 95.8%, 87.6%, 85.1%, and 85.7%, respectively. The Alns 1-encoding cDNA was ligated into expression plasmid, pKP 1500, and expressed in Escherichia coli as a full- length nonfusion protein. The recombinant protein was able to bind specific IgE antibodies present in sera of alder pollen-allergic subjects. However, COOH terminally truncated form of Aln s 1 had no IgE-binding capacity