title: Multiple Amb a I allergens demonstrate specific reactivity with IgE and T cells from ragweed-allergic patients.
abstract: The relationship between the structure and abundance of an inhaled protein and its potential for causing an allergic response is unknown. This study analyzes Amb a I, a family of related proteins formerly known as Ag E, that comprise the major allergens of short ragweed (Ambrosia artemisiifolia). T cells isolated from ragweed allergic patients were shown to proliferate in response to purified Amb a I.1 protein from pollen in in vitro secondary cultures, demonstrating the presence of T cell stimulatory epitopes in Amb a I.1. Three recombinant forms of Amb a I (Amb a I.1, Amb a I.2, and Amb a I.3) obtained as cDNA derived from pollen mRNA were expressed in bacteria. All three recombinant forms were shown to be specifically recognized by pooled ragweed-allergic human IgE on immunoblots, confirming these gene products are important allergens. An examination of immunoblots probed with sera derived from allergic patients revealed a variation in IgE binding specificity. A minority of patients' IgE exclusively reacted with recombinant Amb a I.1, whereas most patients' IgE reacted with Amb a I.1 as well as Amb a I.2 and Amb a I.3 proteins. A detailed examination of the reactivity of T cells derived from 12 allergic patients to these recombinant Amb a I forms revealed that these allergens are all capable of stimulating T cell proliferation in in vitro assays. It is concluded that the allergic response to ragweed pollen in most allergic patients is composed of a reaction to multiple related Amb a I proteins at both the B and T cell levels.
authors.affiliation: ImmuLogic Pharmaceutical Corporation, Cambridge, MA 02139.
authors.forename: J F
authors.initials: JF
authors.lastname: Bond
authors.forename: R D
authors.initials: RD
authors.lastname: Garman
authors.forename: K M
authors.initials: KM
authors.lastname: Keating
authors.forename: T J
authors.initials: TJ
authors.lastname: Briner
authors.forename: T
authors.initials: T
authors.lastname: Rafnar
authors.forename: D G
authors.initials: DG
authors.lastname: Klapper
authors.forename: B L
authors.initials: BL
authors.lastname: Rogers
mesh_terms: D000485:Allergens / Q000032:analysis / Q000276:immunology*; D002478:Cells, Cultured; D000939:Epitopes / Q000032:analysis; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology; D011058:Pollen / Q000032:analysis; D011994:Recombinant Proteins / Q000032:analysis; D006255:Rhinitis, Allergic, Seasonal / Q000209:etiology / Q000276:immunology* / Q000628:therapy; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000485:Allergens; D000939:Epitopes; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E