Maize IgE binding proteins: each plant a different profile?

Abstract

Background: Allergies are nearly always triggered by protein molecules and the majority of individuals with documented immunologic reactions to foods exhibit IgE hypersensitivity reactions. In this study we aimed to understand if natural differences, at proteomic level, between maize populations, may induce different IgE binding proteins profiles among maize-allergic individuals. We also intended to deepen our knowledge on maize IgE binding proteins.

Results: In order to accomplish this goal we have used proteomic tools (SDS-PAGE and 2-D gel electrophoresis followed by western blot) and tested plasma IgE reactivity from four maize-allergic individuals against four different protein fractions (albumins, globulins, glutelins and prolamins) of three different maize cultivars. We have observed that maize cultivars have different proteomes that result in different IgE binding proteins profiles when tested against plasma from maize-allergic individuals. We could identify 19 different maize IgE binding proteins, 11 of which were unknown to date. Moreover, we found that most (89.5%) of the 19 identified potential maize allergens could be related to plant stress.

Conclusions: These results lead us to conclude that, within each species, plant allergenic potential varies with genotype. Moreover, considering the stress-related IgE binding proteins identified, we hypothesise that the environment, particularly stress conditions, may alter IgE binding protein profiles of plant components.

Figure 1

SDS-PAGE of four protein fractions from three different maize varieties. Protein fractions: Prol (Prolamins), Glut (Glutelins), Glob (Globulins) and Alb (Albumins), (30 μg protein/lane). The maize varieties tested were: a- maize commercial line Tietar, b- inbred line PB 269 (FLINT type), c- inbred line PB 369 (DENT type). M- Protein molecular weight marker (10⁻³).

Figure 2

Western blot with plasmas from four maize-allergic individuals (see Table1for information). Left panel: chemiluminescence films; Right panel: chemiluminescence films over pre-coloured nitrocellulose membranes; Protein fractions: Prol (Prolamins), Glut (Glutelins), Glob (Globulins) and Alb (Albumins); Maize tested varieties: a- maize commercial line Tietar, b- inbred line PB 269 (FLINT type), c- inbred line PB 369 (DENT type). Molecular weights (10⁻³) are indicated.

Figure 3

IgE immunoblot reactivity assay of plasma from maize-allergic individuals (Table1for information) against albumins protein fraction. Red arrows represent immunoreactive spots exclusively detected in individual 1, blue arrows represent immunoreactive spots exclusively detected in individual 2 and green arrows represent spots detected with plasmas from both patients. Molecular weights (10⁻³) are indicated.

Figure 4

IgE immunoblot reactivity assay of plasma from maize-allergic individuals (Table1for information) against globulins protein fraction. Red arrows represent immunoreactive spots exclusively detected in individual 1, blue arrows represent immunoreactive spots exclusively detected in individual 2 and green arrows represent spots detected with plasmas from both patients. Molecular weights (10⁻³) are indicated.

Figure 5

IgE immunoblot reactivity assay of plasma from maize-allergic individual 1 (Table1for information) against prolamins protein fraction. Molecular weights (10⁻³) are indicated.