A CDNA CLONE CODING FOR A NOVEL ALLERGEN, CLA-H-III, OF CLADOSPORIUM-HERBARUM IDENTIFIED AS A RIBOSOMAL P-2-PROTEIN

Mold allergens represent a major cause of atopic disorders. Progress i n the molecular characterization of allergens has been hampered by bat ch-to-batch variation and poor yields in mold extracts. In the present study, we established a cDNA library in lambda ZAP II by using mRNA i solated from a major allergen-producing mold, Cladosporium herbarum. F rom this library, a novel allergen has been cloned and sequenced. The clone encodes a full length protein of 111 amino acids with a molecula r mass of 11.1 kDa and pl of 3.94. By using sequence homology analysis , the allergen was found to belong to the ribosomal P-2 protein family . Approximately 60% peptide sequence homology was found between the cl oned protein and other known fungal ribosomal P-2 proteins. In additio n to conserved C-terminal sequences and serine blocks for phosphorylat ion in all eukaryotic ribosomal P-2 proteins, this protein also contai ns a potential N-glycosylation site at position 15-17. Northern blots demonstrated that mRNA molecules of this gene are present even at]ate stages of culture. The gene was expressed in Escherichia coli by using the pMAL-2c system, and murine antisera against the recombinant aller gen (rCh2.1) were generated. The antisera revealed that the native all ergen corresponding to rCh2.1 was present in extracts prepared by grin ding mycelia under liquid nitrogen in the presence of protease inhibit ors, but absent in extracts prepared by conventional methods. This res ult indicates the usefulness of recombinant allergens in characterizat ion and standardization of mold allergenic extracts.