title: Antisense-mediated silencing of a gene encoding a major ryegrass pollen allergen.
abstract: Type 1 allergic reactions, such as hay fever and allergic asthma, triggered by grass pollen allergens are a global health problem that affects approximately 20% of the population in cool, temperate climates. Ryegrass is the dominant source of allergens because of its prodigious production of airborne pollen. Lol p 5 is the major allergenic protein of ryegrass pollen, judging from the fact that almost all of the individuals allergic to grass pollen show presence of serum IgE antibodies against this protein. Moreover, nearly two-thirds of the IgE reactivity of ryegrass pollen has been attributed to this protein. Therefore, it can be expected that down-regulation of Lol p 5 production can significantly reduce the allergic potential of ryegrass pollen. Here, we report down-regulation of Lol p 5 with an antisense construct targeted to the Lol p 5 gene in ryegrass. The expression of antisense RNA was regulated by a pollen-specific promoter. Immunoblot analysis of proteins with allergen-specific antibodies did not detect Lol p 5 in the transgenic pollen. The transgenic pollen showed remarkably reduced allergenicity as reflected by low IgE-binding capacity of pollen extract as compared with that of control pollen. The transgenic ryegrass plants in which Lol p 5 gene expression is perturbed showed normal fertile pollen development, indicating that genetic engineering of hypoallergenic grass plants is possible.
authors.affiliation: Plant Molecular Biology and Biotechnology Laboratory, Institute of Land and Food Resources, University of Melbourne, Parkville, Victoria 3052, Australia. p.bhalla@landfood.unimelb.edu.au
authors.forename: P L
authors.initials: PL
authors.lastname: Bhalla
authors.forename: I
authors.initials: I
authors.lastname: Swoboda
authors.forename: M B
authors.initials: MB
authors.lastname: Singh
mesh_terms: D000485:Allergens / Q000235:genetics* / Q000502:physiology; D007073:Immunoglobulin E / Q000276:immunology; D008129:Lolium / Q000276:immunology*; D030821:Plants, Genetically Modified; D011058:Pollen / Q000276:immunology*; D016372:RNA, Antisense / Q000502:physiology*; D014170:Transformation, Genetic
chemical_list: D000485:Allergens; D016372:RNA, Antisense; D007073:Immunoglobulin E