[Construction and expression of a chimeric gene with T-/B-cell epitopes of major allergen group 1 from Dermatophagoides farina].

OBJECTIVE: To construct and express a chimeric gene with T-/B-cell epitopes of the major allergen group 1 from Dermatophagoidesfarina (Der f 1). METHODS: Two chimeric genes, Der f 1A and Der f 1B, were synthesized as B1-T1-B2-T2- B3-T3-B4-T4-B5-T5-B6 and B1-B2-B3-B4-B5-B6-T1-T2-T3-T4-T5 pattens. Two recombinant vectors, pET-28a(+)-Der f 1A and pET-28a(+)-Der f 1B, were constructed for prokaryotic expression. These chimeric genes were induced by 1 mmol/L IPTG (final concentration), digested with restriction enzymes and sequenced. The chimeric proteins were analyzed by SDS-PAGE and Western blotting. RESULTS: After digestion by restriction enzymes and sequencing, the recombinant vectors were constructed successfully. The specific bands for chimeric proteins were visible by SDS-PAGE and Western blotting, suggesting that these proteins were purified successfully. Further analyses were performed for IgE-binding properties of Der f 1A and Der f 1B to sera from patients sensitized to house dust mite. Compared with the parental allergens Der f 1, Der f 1A and Der f 1B had reduced IgE -binding capacity (both P < 0.05), whereas the difference between Der f 1A and Der f 1B was not statistically significant (P > 0.05). CONCLUSION: Two chimeric proteins are expressed successfully, which contain T-/B-cell epitopes of Der f 1 and provide a basis for specific immunotherapy.