title: Transaldolases are novel and immunoglobulin E cross-reacting fungal allergens.
abstract: BACKGROUND
  Mould-induced atopic respiratory diseases are a worldwide problem. Characterization of fungal allergens is of major clinical importance.
  
  
  OBJECTIVE
  We identified a novel transaldolase family allergen of Cladosporium and Penicillium species.
  
  
  METHODS
  Fungal allergens were identified by immunoblotting, peptide mass mapping and partial sequencing, cDNA cloning and IgE epitope mapping.
  
  
  RESULTS
  A 36.5 kDa IgE-binding component in a partially purified C. cladosporioides preparation was identified. Mass spectrometric analyses suggest that this novel IgE-reacting allergen is a transaldolase. A corresponding full-length 1246 bp cDNA encoding a polypeptide of 325 residues was isolated. The newly identified transaldolase allergen has been designated as Cla c 14.0101. The cDNA encoding the Pencillium chrysogenum transaldolase was isolated by RT-PCR according to the cDNA sequence encoding a P. chrysogenum Wisconsin 54-1255 hypothetical protein. The purified rCla c 14.0101 protein reacted with IgE antibodies in 10 (38%) of 26 Cladosporium cladosporioides-sensitized asthmatic patients. Nine of the 10 rCla c 14.0101-positive sera have IgE binding against the recombinant Penicillium transaldolase (rPen ch 35.0101). Among the eight fungal transaldolase-positive sera tested, three showed IgE binding against the recombinant human transaldolase. To determine cross-reactivity between the Cladosporium and Penicillium fungi, IgE cross-reactivity was detected between these two fungal transaldolase allergens by inhibition assays. Both the N- and the C-terminal fragments of Cla c 14.0101 were recognized by IgE antibodies. The C-terminal IgE-reacting determinant was narrowed down to a region encompassing Thr257 to Ser278 of Cla c 14.0101. It was mapped onto a loop-like structure of a 3D model constructed for Cla c 14.0101.
  
  
  CONCLUSIONS
  We identified transaldolase as a novel and IgE cross-reactive allergen family of C. cladosporioides and P. chrysogenum. In addition, an IgE-reacting fragment (Thr257 to Ser278) was pinpointed to a loop-like structure on Cla c 14.0101. Results obtained provide important information in clinical mould allergy.
authors.affiliation: Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: H
authors.initials: H
authors.lastname: Chou
authors.forename: M F
authors.initials: MF
authors.lastname: Tam
authors.forename: C-H
authors.initials: CH
authors.lastname: Chiang
authors.forename: C-T
authors.initials: CT
authors.lastname: Chou
authors.forename: H-Y
authors.initials: HY
authors.lastname: Tai
authors.forename: H-D
authors.initials: HD
authors.lastname: Shen
mesh_terms: D000485:Allergens / Q000097:blood / Q000276:immunology*; D000946:Antigens, Fungal / Q000097:blood / Q000276:immunology*; D001249:Asthma / Q000097:blood / Q000276:immunology* / Q000382:microbiology; D002963:Cladosporium / Q000201:enzymology / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D010408:Penicillium chrysogenum / Q000201:enzymology / Q000276:immunology*; D014153:Transaldolase / Q000097:blood / Q000276:immunology*
chemical_list: D000485:Allergens; D000946:Antigens, Fungal; D007073:Immunoglobulin E; D014153:Transaldolase