Identification of IgG cross-reactive 11S globulins homologous to Sin a 2 in tree nut extracts. A) SDS-PAGE and Coomassie Blue staining (CBS) of 40 μg/lane of mustard, almond, hazelnut, walnut, pistachio and peanut protein extracts. B) Reactivity of the anti-Sin a 2 serum diluted 1/50000 (lanes I) to mustard, almond, hazelnut, walnut, pistachio and peanut protein extracts (50 μg/lane). A pre-immune rabbit serum (lanes P) was used at the same dilution as negative control. Molecular mass markers are displayed in the left margin.