Rapid Production of Recombinant Allergens in Nicotiana benthamiana and Their Impact on Diagnosis and Therapy

Background: Type I allergies are immunological disorders that afflict a quarter of the world’s population. Recombinant allergens have improved the diagnosis of allergic diseases and allow the formulation of new therapeutic approaches. Over 50% of all allergens are of plant origin. Objective: We have applied a novel method of overexpressing plant allergens in the tobacco-related species Nicotiana benthamiana.Method: This method is based on the use of a chimeric tobacco mosaic virus that harbors a foreign gene sequence and directs its transcription after the infection of the host plant. Results: We have expressed the model allergen Bet v 1, the major birch pollen allergen, and two Hevea brasiliensis latex allergens, the spina-bifida-associated allergens Hev b 1 and Hev b 3, in N. benthamiana using such a viral vector. Bet v 1, Hev b 1 and Hev b 3 produced by this method were recognized by patients’ IgE suggesting that the plant-produced allergens were properly folded. Nonpurified Bet v 1 expressed in N. benthamiana leaves had the same immunogenicity as purified Bet v 1 expressed in Escherichia coli or natural Bet v 1 when tested in a murine model of type I allergy. Conclusion: We conclude that this plant expression system offers a viable alternative to fermentation-based production of allergens in bacteria or yeasts.