Type of Document Thesis Author Tawde, Pallavi D Author's Email Address email@example.com URN etd-11172004-151724 Title Allergenic Cross-reactivity between Cashew and Pistachio Nuts Degree Master of Science Department Biological Science, Department of Advisory Committee
Advisor Name Title Kenneth Roux Committee Chair Shridhar Sathe Committee Member Tom Keller Committee Member Keywords
- Tree Nuts
Date of Defense 2004-11-15 Availability unrestricted AbstractABSTRACT
Title: Allergenic cross-reactivity between cashew and pistachio nuts
Rationale: Cashew and pistachio belong to Anacardiaceae family and strong allergenic cross-reactivity between nuts of these two species has been reported. The aim of our study was to identify the cross-reactive allergenic proteins from cashew and pistachio nuts.
Methods: Extracted cashew and pistachio nut proteins were separated by means of 1- and 2-dimensional PAGE. Pooled human sera from cashew-allergic patients was tested for reactivity to soluble cashew and pistachio proteins by IgE immunoblotting after one-dimensional (1-D) and 2-D electrophoresis. The identities of the IgE-reactive bands from the pistachio immunoblot were further analyzed by means of N-terminal amino acid sequencing and comparison to previously published data from the cashew. ELISAs were performed using individual sera from subjects with cashew and tree nut allergy to assess the degree of IgE reactivity to cashew and pistachio nut extracts. Inhibition ELISA studies were conducted to assess the degree of allergenic cross-reactivity between cashew and pistachio nuts.
Results: IgE immunoblots of cashew and pistachio extract probed with cashew-allergic sera identified proteins of 35kDa, 22kDa, and 7-9kDa. N-terminal amino acid sequencing of the IgE-reactive spots from pistachio immunoblot identified them as the acidic subunit, basic subunit of 11S globulin and 2S albumin seed storage proteins respectively. Seed storage proteins are known food allergens in cashew and have been designated as Ana o 1 (7S globulin), Ana o 2 (11S globulin) and Ana o 3 (2S albumin). ELISA results with ten individual cashew-allergic sera (two out of the ten patients have pistachio allergy, and the remaining eight patients had never eaten pistachio) showed IgE reactivity to both cashew and pistachio nut. Inhibition ELISA demonstrated that pre-incubation of sera with pistachio extract resulted in a marked decrease in IgE binding to cashew extract, and vice versa indicating allergenic cross-reactivity.
Conclusion: The results demonstrate the presence of cross-reactive B cell epitopes on cashew and pistachio nut allergens. The plant taxonomic classification of cashew and pistachio nuts does appear to predict allergenic cross-reactivity.
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