Structural features, IgE binding and preliminary clinical findings of the 7kDa Lipid Transfer Protein from tomato seeds

Ivana Giangrieco; Claudia Alessandri; Chiara Rafaiani; Mario Santoro; Sara Zuzzi; Lisa Tuppo; Maurizio Tamburrini; Rossana D'Avino; Maria Antonietta Ciardiello; Adriano Mari

doi:10.1016/j.molimm.2015.02.025

Structural features, IgE binding and preliminary clinical findings of the 7kDa Lipid Transfer Protein from tomato seeds

Mol Immunol. 2015 Aug;66(2):154-63. doi: 10.1016/j.molimm.2015.02.025. Epub 2015 Mar 16.

Affiliations

¹ Institute of Biosciences and BioResources, CNR, Via Pietro Castellino 111, I-80131 Naples, Italy.
² Center for Molecular Allergology, IDI-IRCCS, Rome, Italy; Associated Centres for Molecular Allergology, Rome and Latium, Italy.
³ Center for Molecular Allergology, IDI-IRCCS, Rome, Italy; Associated Centres for Molecular Allergology, Rome and Latium, Italy. Electronic address: adriano.mari@caam-allergy.com.

PMID: 25791776
DOI: 10.1016/j.molimm.2015.02.025

Abstract

Allergic reactions caused by 9kDa Lipid Transfer Proteins (9k-LTP), such as Pru p 3, have been widely investigated, whereas a possible contribution of components of 7kDa LTP (7k-LTP) sub-family in triggering allergic symptoms has been overlooked so far. With the aim to investigate the contribution of 7k-LTPs to the food allergies, we have identified, isolated and characterised a tomato seed 7k-LTP (Sola l 7k-LTP). The protein was purified by chromatographic separations, identified by direct protein sequencing and mass spectrometry and a molecular model was built. Functional evaluation of the allergen has been performed by skin testing. Sola l 7k-LTP consists of 68 amino acids producing a molecular mass of 7045Da and displays 41% sequence identity with Pru p 3, the allergenic 9k-LTP from peach. IgE antibodies specifically recognising Sola l 7k-LTP were found within the population claiming tomato ingestion-related symptoms, but also in subjects tolerant on tomato exposure. A few subjects were mono-sensitised to Sola l 7k-LTP, which is biologically active as shown by the positive skin test. In line with the immunological results, the molecular model shows structural similarities between the IgE binding regions of the two sub-families. Therefore, Sola l 7k-LTP shares some structural and immunological features with Pru p 3, but it also displays individual features that could be responsible for mono-specific IgE binding. In conclusion, Sola l 7k-LTP is a new identified allergenic LTP, the description of which may contribute to the improvement of allergy diagnosis and to the formulation of a safe and personalised diet. In addition, to avoid current confusing classifications, a new nomenclature policy for LTP sub-families is proposed in this paper. We now suggest that 7-kDa LTP (so far named LTP2) be renamed 7k-LTP and 9-kDa LTP (so far named LTP1) be renamed 9k-LTP.

Keywords: 7kDa LTP; Food allergy; IgE reactivity; Molecular model; Solanum lycopersicum; Tomato seeds.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Amino Acid Sequence
Antigens, Plant / chemistry
Antigens, Plant / immunology
Binding Sites
Carrier Proteins / chemistry
Carrier Proteins / immunology*
Carrier Proteins / isolation & purification
Child
Child, Preschool
Female
Food Hypersensitivity / immunology*
Food Hypersensitivity / physiopathology
Humans
Immunoglobulin E / chemistry
Immunoglobulin E / immunology*
Male
Middle Aged
Models, Molecular
Molecular Sequence Data
Molecular Weight
Plant Proteins / chemistry
Plant Proteins / immunology*
Plant Proteins / isolation & purification
Protein Binding
Protein Conformation
Prunus / chemistry
Prunus / immunology
Seeds / chemistry
Seeds / immunology*
Sequence Alignment
Solanum lycopersicum / chemistry
Solanum lycopersicum / immunology*
Terminology as Topic

Substances

Antigens, Plant
Carrier Proteins
LTP2 protein, plant
Plant Proteins
Pru p 3 allergen
Immunoglobulin E