Protein sequence analysis and mapping of IgE and IgG epitopes of an allergenic 98-kDa Dermatophagoides farinae paramyosin, Der f 11

Background: A 98-kDa mite paramyosin (Der f 11 from Dermatophagoides farina e (Df) is highly allergenic, and its cDNA (Df642) has been cloned. This pap er describes the sequence characteristics and the mapping of the immunodomi nant human IgE and IgG epitopes of Der f 11. Methods: The protein sequence analysis was performed with a combination of FASTA, GCG, and CLUSTAL W computing packages. The whole cDNA insert and its PCR-derived DNA fragments were generated and expressed in E. coli. These o verlapping recombinant peptides (F1 to F5) were used for B-cell epitope map ping with 18 mite-allergic sera by dot immunoassays. Results: Df642 cDNA encodes a partial sequence that contains the 2nd to 26t h 28-residue repeats and lacks the N-terminus and the C-terminus. The seque nce identity of Der f 11 with other known paramyosins is 34-60%. The domina nt IgE epitopes are located in peptides F1 and F4, whereas the dominant IgG epitopes are located in peptides F1 and F2. These peptides are more reacti ve than whole rDf642. Conclusions: Mite paramyosin is very similar to other known paramyosins. Th e human IgE and IgG epitopes are scattered throughout the entire molecule. Data also indicate the presence of unique IgE and IgG epitopes in Der f 11.