Construction of single-chain interleukin-12 DNA plasmid to treat airway hyperresponsiveness in an animal model of asthma

• Published in: Human gene therapy Vol. 12; no. 17; p. 2065
• Main Authors: Lee, Y L, Ye, Y L, Yu, C I, Wu, Y L, Lai, Y L, Ku, P H, Hong, R L, Chiang, B L
• Format: Journal Article
• Language: English
• Published: United States 20.11.2001
• Subjects: Allergens - immunology; Animals; Asthma - genetics; Asthma - immunology; Asthma - pathology; Asthma - therapy; Bronchi - drug effects; Bronchi - immunology; Bronchi - pathology; Bronchoalveolar Lavage Fluid; COS Cells; Disease Models, Animal; Female; Genetic Therapy - methods; Immunotherapy - methods; Inflammation - immunology; Inflammation - pathology; Interleukin-12 - chemistry; Interleukin-12 - genetics; Interleukin-12 - immunology; Interleukin-12 - therapeutic use; Lung - immunology; Lung - pathology; Methacholine Chloride - pharmacology; Mice; Mice, Inbred C57BL; Plasmids - genetics; Transfection; Vaccines, DNA - genetics; Vaccines, DNA - therapeutic use
• ISSN: 1043-0342
• DOI: 10.1089/10430340152677412

Allergic asthma is strongly associated with the airway inflammation caused by the dysregulated production of cytokines secreted by the allergen-specific type-2 T helper (Th2) cells. Interleukin (IL)-12 is a heterodimeric cytokine, which strongly promotes the differentiation of naive CD4(+) T cells to the type-1 T helper (Th1) phenotype and suppresses the expression of Th2 cytokines. Therefore, immunotherapy with IL-12 has been suggested as a possible therapy for asthma. In previous studies, we developed a murine model of airway inflammation based on the purified, house dust-mite allergen Der p 1 (Dermatophagodies pteronyssinus) as a clinically relevant allergen. We hypothesized that the expression of IL-12 in the airway may represent an effective therapy for allergic airway diseases. In this study, we investigate whether the local transfer of the IL-12 gene to respiratory tissues modifies allergic inflammation and airway hyper-responsiveness (AHR) in our disease model. To enhance the in vivo delivery of the IL-12 gene, we expressed the murine single-chain IL-12 protein from a nonviral vector to which the two IL-12 subunits (p35 and p40) were linked by a 14- to 18-amino-acid linker. One of these single-chain IL-12s, containing an 18 amino-acid polypeptide linker, was stably expressed and had a high level of biological activity comparable to that of native IL-12 in vitro. In mice with Der p 1-induced asthma, the local administration of this IL-12 fusion gene into the lungs significantly prevented the development of AHR, abrogated airway eosinophilia, and inhibited type-2 cytokine production. These findings indicate that the local transfer of the single-chain IL-12 gene is effective in modulating pulmonary allergic responses and may be a convenient method for future applications of DNA vaccination.