Oral administration of a mite allergen expressed by zucchini yellow mosaic virus in cucurbit species downregulates allergen-induced airway inflammation and IgE synthesis.
BACKGROUND
Sublingual-swallow immunotherapy in house dust mite-related asthma has a good safety profile and improves respiratory function and bronchial hyperreactivity. Zucchini yellow mosaic virus (ZYMV) is envisaged as a promising viral vector for expressing large quantity of foreign proteins in cucurbit species.


OBJECTIVE
We sought to investigate whether oral feeding of dust mite allergen expressed by ZYMV in a cucurbit species can suppress allergen-induced inflammation and IgE synthesis.


METHODS
An infectious plant virus clone, p35SZYMV2-26, that contains the full-length cDNA to the genomic RNA of a Taiwan isolate of ZYMV, driven by the cauliflower mosaic virus 35S promoter, was engineered as an in vivo viral vector to express Dermatophagoides pteronyssinus group 5 allergen (Der p 5) in cucurbit species. Female BALB/c mice were intraperitoneally sensitized with Escherichia coli bacteria-expressed Der p 5 and orally treated with the virus-expressed Der p 5 (vDer p 5) extracted from the recombinant virus-infected squash plants. Der p 5-specific immunoglobulins were measured by ELISA, and bronchoalveolar lavage assays were used to measure airway inflammation.


RESULTS
Infectivity assays and immunoblotting revealed that large quantities of free-form vDer p 5 are produced in the recombinant virus-infected squash plants. The recombinant virus carried and expressed the Der p 5 allergen in squash plants for at least 1 year after numerous passages. In animal tests, squash extract containing vDer p 5 inhibited Der p 5-specific IgE synthesis and airway inflammation.


CONCLUSIONS
Our results suggest that oral feeding with allergen produced by the plant viral vector provides a novel approach for the therapy of allergic asthma.
Hsu
Ching-Hsiang
CH
Allergy, Immunology and Rheumatology Department, Pediatrics Division, China Medical University, Taichung 402, Taiwan.
Lin
Shih-Shun
SS
Liu
Fang-Lin
FL
Su
Wei-Chih
WC
Yeh
Shyi-Dong
SD
D000284:Administration, Oral; D000595:Amino Acid Sequence; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000008:administration & dosage / Q000276:immunology*; D060829:Arthropod Proteins; D001249:Asthma / Q000628:therapy*; D001483:Base Sequence; D003888:Desensitization, Immunologic; D015536:Down-Regulation; D005260:Female; D007073:Immunoglobulin E / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D017800:Potyvirus / Q000235:genetics*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C451239:Dermatophagoides pteronyssinus antigen p 5; D011994:Recombinant Proteins; D007073:Immunoglobulin E