Efficacy of oral immunotherapy with a rice-based edible vaccine containing hypoallergenic Japanese cedar pollen allergens for treatment of established allergic conjunctivitis in mice

Background: We have previously shown that prophylactic oral administration of transgenic rice seeds expressing hypoallergenic modified antigens suppressed the development of allergic conjunctivitis induced by Japanese cedar pollen. We have now investigated the efficacy of oral immunotherapy with such transgenic rice for established allergic conjunctivitis in mice. Methods: BALB/c mice were sensitized with two intraperitoneal injections of Japanese cedar pollen in alum, challenged with pollen in eyedrops, and then fed for 16 days with transgenic rice seeds expressing modified Japanese cedar pollen allergens Cry j 1 and Cry j 2 or with nontransgenic rice seeds as a control. They were then challenged twice with pollen in eyedrops, with clinical signs being evaluated at 15 min after the first challenge and the eyes, blood, spleen, and lymph nodes being isolated at 24 h after the second challenge. Results: The number of eosinophils in the conjunctiva and the clinical score for conjunctivitis were both significantly lower in mice fed the transgenic rice than in those fed nontransgenic rice. Oral vaccination with transgenic rice seeds also resulted in a significant increase in the production of IFN-γ by splenocytes, whereas it had no effect on the number of CD4+CD25+Foxp3+ regulatory T cells in the spleen or submandibular or mesenteric lymph nodes. Conclusions: Oral administration of transgenic rice seeds expressing hypoallergenic allergens ameliorated allergic conjunctivitis in the established setting. Such a rice-based edible vaccine is potentially both safe and effective for oral immunotherapy in individuals with allergic conjunctivitis

Null Mutation of the MdACS3 Gene, Coding for a Ripening-Specific 1-Aminocyclopropane-1-Carboxylate Synthase, Leads to Long Shelf Life in Apple Fruit1[W][OA]

Expression of MdACS1, coding for 1-aminocyclopropane-1-carboxylate synthase (ACS), parallels the level of ethylene production in ripening apple (Malus domestica) fruit. Here we show that expression of another ripening-specific ACS gene (MdACS3) precedes the initiation of MdACS1 expression by approximately 3 weeks; MdACS3 expression then gradually decreases as MdACS1 expression increases. Because MdACS3 expression continues in ripening fruit treated with 1-methylcyclopropene, its transcription appears to be regulated by a negative feedback mechanism. Three genes in the MdACS3 family (a, b, and c) were isolated from a genomic library, but two of them (MdACS3b and MdACS3c) possess a 333-bp transposon-like insertion in their 5′ flanking region that may prevent transcription of these genes during ripening. A single nucleotide polymorphism in the coding region of MdACS3a results in an amino acid substitution (glycine-289 → valine) in the active site that inactivates the enzyme. Furthermore, another null allele of MdACS3a, Mdacs3a, showing no ability to be transcribed, was found by DNA sequencing. Apple cultivars homozygous or heterozygous for both null allelotypes showed no or very low expression of ripening-related genes and maintained fruit firmness. These results suggest that MdACS3a plays a crucial role in regulation of fruit ripening in apple, and is a possible determinant of ethylene production and shelf life in apple fruit