Lipid Transfer Protein: A Pan-Allergen in Plant-Derived Foods That Is Highly Resistant to Pepsin Digestion

Abstract

Background: Lipid transfer proteins (LTPs) are stable and highly conserved proteins of around 10 kD. They have recently been identified as allergens in fruits of the Rosaceae family. Objective: The aim of this study was to investigate whether the highly conserved structure of LTPs justifies a designation as a true pan-allergen, and to study the role of protein stability in allergenicity. Methods: Thirty-eight patients with a positive skin prick test to Rosaceae fruit extracts were characterized by interviews and skin prick tests. To investigate IgE cross-reactivity between Rosaceae and non-Rosaceae LTPs, RAST and RAST inhibition as well as ELISA and ELISA inhibition were performed, using whole food extracts and purified natural and recombinant LTPs. To address the role of protein stability in the allergenicity of LTP, fruit extracts and LTPs were digested with pepsin. Results: IgE antibodies to Rosaceae LTPs cross-reacted with a broad range of non-Rosaceae vegetable foods. Inhibition studies with purified natural and recombinant LTPs confirmed the role of LTP in this cross-reactivity. Many of the patients with this type of cross-reactive IgE antibodies had a clinical food allergy. In contrast to the typical birch Rosaceae cross-reactive patients, the oral allergy syndrome was frequently accompanied by more severe and systemic reactions. IgE reactivity to LTP was shown to be resistant to pepsin treatment of the allergen. Conclusion: LTP is a true pan-allergen with a degree of cross-reactivity comparable to profilin. Due to its extreme resistance to pepsin digestion, LTP is a potentially severe food allergen.

Linkage map positions and allelic diversity of two Mal d 3 (non-specific lipid transfer protein) genes in the cultivated apple (Malus domestica)

“…The peach fruit is one of the most frequent causes of food allergy in Mediterranean populations and is considered to be the primary sensitizing agent in this type of food allergy (Asero et al 2000). Garcia-Casado et al (2003) used the peach allergen, Pru p 3, as a model to find IgE epitopes.…”

Next-generation protein-rich potato expressing the seed protein gene AmA1 is a result of proteome rebalancing in transgenic tuber

“…The potent food allergens are known to be very stable in in vitro pepsin digestion, whereas most dietary proteins are readily digestible (27). The pepsin digestibility assay is thus considered one of the major ways to identify food allergens (28)(29)(30).…”

Molecular Properties of Plant Food Allergens: A Current Classification into Protein Families

“…nsLTPs display a wide distribution and therefore are considered as pan-allergens with sequences available from fruits, nuts, seeds, and vegetables. Thermostability as well as resistance to proteolysis and harsh pH conditions renders them potent class I food allergens [23]. They accumulate at high concentrations in the outer epidermal layers of plant organs explaining for instance the strong allergenicity of fruit peels compared to pulps as shown for Rosaceae fruits [24].…”