Identification of an obeche (Triplochiton scleroxylon) wood allergen as a class I chitinase

Allergy. 2005 Jun;60(6):808-14. doi: 10.1111/j.1398-9995.2005.00794.x.


Background: Wood dust is known to cause allergic occupational asthma and obeche (Triplochiton scleroxylon) is a prominent exponent in this field. However, the knowledge about wood allergens is still limited. The aim of this study was to identify and characterize obeche wood allergens.

Methods: Obeche extracts were prepared from freshly ground in comparison to 7 years stored wood dust and investigated by Sodium dodecyl sulfate-polyacrylamid gel electrophoresis, enzyme-linked allergosorbent test and immunoglobulin (Ig)E-immunoblot. Allergens were detected by specific IgE of seven obeche allergic patients' sera and protein analysis was performed by mass spectrometry. Cross-reactivity was demonstrated by ImmunoCAP-inhibition with sera of seven obeche and four latex-allergic patients.

Results: Obeche extracts showed different protein pattern and IgE-binding capacities depend on the age of the wood dust. A 38 kDa protein was identified as major obeche wood allergen, detected by six of seven (85%) obeche allergic patients' sera and was entitled as Trip s 1. Trip s 1 is homologous to plant class I chitinases and exhibited enzyme activity demonstrated by chitinolysis. Co-recognition or cross-reactivity of Trip s 1 according to structural similarity was seen in sera of latex allergic patients. IgE inhibition studies with obeche as solid phase and Trip s 1 and latex hevein as inhibitor demonstrated that Trip s 1 was a more effective inhibitor in obeche as well as in latex allergic patients' sera.

Conclusions: Trip s 1 is a new obeche wood allergen of the plant class I chitinase family. This finding may explain the dominant role of obeche in sensitization against wood dust.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Allergens / adverse effects
  • Allergens / chemistry
  • Allergens / immunology*
  • Asthma / blood
  • Asthma / etiology
  • Chitin / metabolism
  • Chitinases / chemistry
  • Chitinases / immunology*
  • Cross Reactions
  • Dust / analysis
  • Humans
  • Immune Sera
  • Immunoglobulin E / blood
  • Latex Hypersensitivity / immunology
  • Malvaceae*
  • Middle Aged
  • Molecular Weight
  • Occupational Diseases / blood
  • Occupational Diseases / etiology
  • Plant Components, Aerial / immunology
  • Plant Extracts / chemistry
  • Plant Proteins / chemistry
  • Plant Proteins / immunology*
  • Plant Proteins / metabolism
  • Wood*


  • Allergens
  • Dust
  • Immune Sera
  • Plant Extracts
  • Plant Proteins
  • Chitin
  • Immunoglobulin E
  • Chitinases
  • chitinase C