Over the last ten years, genes encoding food allergens have been cloned and sequenced but no consensus sequences or motifs associated with allergy have been determined. Indeed, my lab has cloned genes encoding 2 of the major English walnut kernel allergens, the 2S albumin and a vicilin-like seed storage protein, Jug r 1 and Jug r 2, respectively. Plant seed allergy is often life-threatening and permanent. Individuals with walnut allergy, for instance, can have high levels of specific IgE against several different, non-cross-reactive proteins in their sera into their seventh decade. Most patients who have life-threatening walnut allergy have a childhood history of atopic dermatitis (AD), in which it has been demonstrated that there is more of a tendency to develop IgE against multiple environmental and food allergens. Even in the face of this however, most children with AD are tolerant of most foods. The major thesis of this proposal is that plant seed proteins, because of the way they are packaged as whole proteins in the plant protein body storage organelle with associated lectins, enzymes, and polyphenolic compounds, are able to stimulate the APC in atopic persons to modulate the cytokine milieu towards increased IL-4 and IL-13, inducing an IgE response. As a prototype seed to study, the walnut (Juglans regia) will be used based on the availability of human subjects, recombinant allergens, multiple protein preparations, fractionated polyphenolics and its importance as a tree nut allergen. To characterize the APC-T cell interaction, T cell lines will be established from individuals with walnut food allergy and individuals with atopic dermatitis without food allergy. The proliferative response and Th2 related cytokine mRNA transcription will be assessed in response to different antigen packages delivered to the APC: recombinant Jug r 1 and Jug r 2, peptide fragments, whole purified proteins (albumins and large globulins), purified protein bodies (lectins and enzymes present), total walnut extract (pellicle polyphenolics and oil body lipids present), and the above protein sources with a quantified walnut total polyphenolic fraction added (rich in quercetin and ellagic acid). The above data will significantly advance our knowledge of the immunobiology of plant seed allergy.
| Comstock, Sarah S; Gershwin, Laurel J; Teuber, Suzanne S (2010) Effect of walnut (Juglans regia) polyphenolic compounds on ovalbumin-specific IgE induction in female BALB/c mice. Ann N Y Acad Sci 1190:58-69 |
| Robotham, Jason M; Wang, Fang; Seamon, Vanessa et al. (2005) Ana o 3, an important cashew nut (Anacardium occidentale L.) allergen of the 2S albumin family. J Allergy Clin Immunol 115:1284-90 |
| Wang, Fang; Robotham, Jason M; Teuber, Suzanne S et al. (2003) Ana o 2, a major cashew (Anacardium occidentale L.) nut allergen of the legumin family. Int Arch Allergy Immunol 132:27-39 |
