[Sequence polymorphism of major house dust mite allergens].

Objective: To determine the sequence variation of the groups 1 and 2 allergens from Dermatophagoides pteronyssinus and Dermatophagoides farinae in different geographical regions.

Methods: RNAs were isolated from the whole bodies, eggs and entire culture of mites (D. farinae) from South China and European commercialized D. pteronyssinus and D. farinae. Sequences of prepeptide, propeptide and mature peptide fragments in group 1, and prepeptide and mature peptide fragments in group 2 were determined from cDNA produced by PCR. All the sequences were compared with the corresponding standards in GenBank.

Results: Der p 1.0105 was the major variant found in European commercialized Der p 1 clones, where amino acid variations appeared sporadic, except for frequent substitutions shown in residues 124, 50 and 19, and eight novel homologous variants were identified. Derp 2.0104 was mostly detected in clones from European commercialized Der p 2, where amino acid substitutions were predominant in residues 40, 47, 111 and 114, and six novel homologous variants were identified. Very few amino acid sequence substitutions were found among South China based Der f 1 clones, where three novel homologous variants were identified. As compared with European commercialized ones, a number of homologous variants were recognized unique to South China based Der f 2 clones where six novel homologous variants were identified. There was no significant difference in major allergens among variants from the whole mite bodies, eggs or the entire culture.

Conclusion: There is a difference among the predominant variants of major house dust mite allergens in different geographical regions.