Cloning and molecular characterization of Hev b 3, a spina-bifida-associated allergen from Hevea brasiliensis latex.
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Biomedical subjects
Publications and source records attributed to B Niggemann.
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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.
The aim of our study was to investigate the effect of platelet-activating factor on human bronchial ciliary beat frequency (CBF) ex vivo. Brush biopsies were obtained from eight children (mean age 6.6 years) who underwent bronchoscopy for clinical reasons (i.e., foreign body aspiration, chronic cough, stridor). Immediate measurement of CBF by phase-contrast microscopy and photoelectric technique was performed before further treatment, and then on three subsamples: after adding platelet-activating factor (PAF) (10(-5) M); after adding the inhibitor WEB 2086 (10(-4) M); and after adding both PAF and WEB 2086. Addition of 10(-5) M PAF reduced mean CBF by 2.1 Hz to 9.2 Hz (p < 0.05). The inhibitory effect of PAF was completely reversed by the addition of the PAF-inhibitor WEB 2086, whereas WEB 2086 alone did not significantly influence CBF. Optimum PAF concentration had been determined in previous dose-response experiments. Our data indicates that PAF involved in airway inflammation contributes to a decrease in mucociliary clearance in humans.