The recombinant expression of two pollen allergens using plant-viral and yeast expression systems.
Moehnke, Marcie H.
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Allergic disease causes much distress within industrialized areas of the world, affecting approximately a quarter of the population in such areas. Current immunotherapy involves the administration of increasing concentrations of crude allergen extracts over a period of time, in an attempt to switch the individual's allergic response to that of a non-allergic individual. Such therapy is largely ineffective, especially for cedar hypersensitivity where only 30% of individuals respond after two years of weekly injections, and unwanted and sometimes life-threatening side effects can accompany specific immunotherapy. In an effort to increase its efficacy, as well as circumvent these negative side effects, recombinant DNA technology is being used to produce recombinant allergens that will take the place of crude allergen extracts found in immunotherapy injections. A main cause of allergic disease within south central Texas is pollen produced by mountain cedars, Juniperus ashei. In one study, I cloned a particular mountain cedar allergen, Jun a 3, into a tobacco mosaic virus vector under the regulation of a subgenomic promoter. Infectious viral transcripts were inoculated onto Nicotiana benthamiana plants, and recombinant Jun a 3 protein was detected within these plants at 21 days post-inoculation. The recombinant protein was able to bind anti-Jun a 3 IgG antibodies as well as IgE from mountain cedar allergic patient sera. A separate study also demonstrated the successful expression of recombinant Jun a 3, but in a yeast expression system. The Jun a 3 cDNA was cloned into a yeast expression vector and transformed into Pichia pastoris cells for expression. Western blotting and ELISA experiments confirmed the recombinant Jun a 3 produced by the yeast bound anti-Jun a 3 IgG antibodies and IgE from allergic patient sera. A third study utilized the tobacco mosaic virus-based plant expression system to produce the main Italian cypress allergen, Cup s 1, from Cupressus sempervirens. This recombinant allergen behaved very similarly to a native cross-reactive allergen in its binding to IgG antibodies and allergic patient sera.