Proteomic Analysis of Lupin Seed Proteins To Identify Conglutin β as an Allergen, Lup an 1

Abstract

Lupin products may be valuable as human foods because of their high protein content and potential anticholesterolemic properties. However, a small percentage of the population is allergic to lupin. In this study, we use in vitro IgE binding and mass spectrometry to identify conglutin beta, a major storage protein, as an allergen in seeds of Lupinus angustifolius and Lupinus albus. Purification of conglutin beta from L. angustifolius flour confirmed that serum IgE binds to this protein. Where IgE in sera recognized lupin proteins on Western blots, it recognized conglutin beta, suggesting this protein is a major allergen for lupin. The L. angustifolius conglutin beta allergen has been designated Lup an 1 by the International Union of Immunological Societies (IUIS) allergen nomenclature subcommittee.

Legume Crops Phylogeny and Genetic Diversity for Science and Breeding

“…A small proportion of the population is allergic to lupin kernel flour; consequently, research is underway to understand the components of lupin seed proteins associated with allergenicity (Goggin et al, 2008). Breeders successfully addressed problems of late maturity caused by a strong vernalization requirement, excessive indeterminate branching and excessive height (Wolko et al, 2011).…”

Immunoreactivity changes during lupin seed storage proteins digestion

“…This protein might correspond to α-subunit of γ-conglutin which is able to bind IgE antibodies [27]. In the literature there can be found contradictory opinion where this interaction is specific or not [17]. The not specific interaction theory can be explained by the fact that γ-conglutin is glycoprotein and can easily interact with glycans moiety of immunoglobulins present in the patients sera [25,27].…”

“…In the case of lupin the most frequent reactions occurred in peanut sensitive individuals [5,6,14]. Fractions of α-and β-conglutin are considered to be the main proteins that cause allergic reactions in patients with known allergies to peanuts [15][16][17]. Recent studies in this subject were carried out by Ballabio et al [18].…”

Digestion susceptibility of seed globulins isolated from different lupin species

“…The ability to bind specific antibodies is especially important for the allergenicity of lupin seeds. The main IgE-binding proteins of lupin have molecular weights in the range from 70 to 60 kDa and 40 kDa (β-conglutin) [21], 30 and 17 kDa (γ-conglutin) [20] and 20 kDa (basic subunit of α-conglutin) [20]. Serious health risk associated with food allergy is the presence of cross-reactions, which in the case of lupin most often occurs with other legumes [18,19].…”

“…In the case of lupin, the most frequently observed cross-reaction is the one with peanut [9,10,18]. The main proteins that cause allergic reactions in patients with known allergies to peanuts are these included in the α-and β-conglutin fractions [19][20][21]. Ballabio et al [22] analysing the allergic reaction in twelve patients with allergy to peanuts found that seven of them reacted positively to β-conglutin.…”