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Molecular polymorphisms of house dust mite allergens
W R Thomas1, K Y Chua, W A Smith
1Division of Molecular Biology, Western Australian Research Institute for Child Health, Princess Margaret Hospital, Perth.
Experimental & Applied Acarology
|November 1, 1992
Summary
This study examines genetic variations in Dermatophagoides pteronyssinus allergens, Der fII and Der fIII. It found high similarity in Der fII sequences and identified multiple molecular forms of Der fIII, with varying allergic reactivity in adults and children.
Area of Science:
- Molecular biology
- Immunology
- Allergen research
Background:
- Previous research established primary amino acid sequences for group I and II allergens from Dermatophagoides mites.
- This study focuses on allergen polymorphisms within species, specifically Dermatophagoides pteronyssinus (Dp).
Purpose of the Study:
- To investigate polymorphisms of Der fII (Dermatophagoides farinae group II) allergens.
- To characterize the group III allergens of Dermatophagoides pteronyssinus (Der fIII).
Main Methods:
- Sequencing of four cDNA clones of Der fII produced by polymerase chain reaction (PCR).
- Comparison of Der fII sequences from different geographical sources (Australia and Japan).
- Isolation and characterization of Der fIII from mite culture using affinity chromatography and Western blotting.
- Radioimmune dot-blot assays to assess allergic reactivity in adults and children.
Main Results:
- High sequence similarity was observed among six Der fII sequences, with only two potential non-conservative changes.
- Nucleotide sequences and 3' untranslated regions of Der fII were conserved, suggesting potential genetic markers.
- Der fIII isolated from spent mite media showed multiple molecular forms (32-, 28-, and 21-kDa) varying between batches.
- Significant allergic reactivity to Der fIII was observed in 83% of adults and 38% of children, primarily to the 32- and 28-kDa forms.
- Murine antisera against Der fIII recognized 32-, 28-, and 21-kDa forms in Dp mite extracts.
Conclusions:
- Der fII allergens exhibit high conservation across different sources.
- Der fIII is a complex allergen with multiple molecular forms, eliciting significant allergic responses in both adults and children.
- The identified Der fIII forms and their differential reactivity warrant further investigation for improved allergy diagnostics and therapeutics.