Lipid transfer protein: a pan-allergen in plant-derived foods that is highly resistant to pepsin digestion.
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.


CONCLUSIONS
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.
Asero
R
R
Ambulatorio di Allergologia, Ospedale Caduti Bollatesi, Bollate, Italy.
Mistrello
G
G
Roncarolo
D
D
de Vries
S C
SC
Gautier
M F
MF
Ciurana
C L
CL
Verbeek
E
E
Mohammadi
T
T
Knul-Brettlova
V
V
Akkerdaas
J H
JH
Bulder
I
I
Aalberse
R C
RC
van Ree
R
R
D000485:Allergens / Q000737:chemistry / Q000276:immunology; D052179:Antigens, Plant; D002352:Carrier Proteins / Q000737:chemistry* / Q000276:immunology*; D003429:Cross Reactions; D004044:Dietary Proteins / Q000009:adverse effects; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D005638:Fruit / Q000009:adverse effects*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D010434:Pepsin A / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; D002352:Carrier Proteins; D004044:Dietary Proteins; D010940:Plant Proteins; C511920:lipid transfer proteins, plant; D007073:Immunoglobulin E; D010434:Pepsin A