Gastro-duodenal digestion products of the major peanut allergen Ara h 1 retain an allergenic potential.
BACKGROUND
The process of gastro-duodenal digestion may play a role in determining the allergenic properties of food proteins. The sensitizing and allergenic potential of digestion products of highly degraded allergens, such as the major peanut allergen Ara h 1, is currently under debate. We evaluated the effect of in vitro gastro-duodenal digestion of Ara h 1 on T cell reactivity and basophil histamine release.


METHODS
An in vitro model of gastro-duodenal digestion was used to investigate changes in the allergenic properties of Ara h 1 using in vitro assays monitoring T cell reactivity (proliferation, cytokine production) and histamine release of basophils from peanut allergic individuals. The digestion process was monitored using an SDS-PAGE gel.


RESULTS
In vitro gastric digestion led to rapid degradation of Ara h 1 into small fragments M(r) L5600. Gastric digestion did not affect the ability of Ara h 1 to stimulate cellular proliferation. Gastro-duodenal digestion significantly reduced its ability to stimulate clonal expansion (P<0,05; Wilxocon's signed rank test). The Th-2 type cytokine polarization of T cells from peanut allergic donors (IFN-gamma/IL-13 ratio and IFN-gamma/IL-4 ratio of CFSE(low) CD4(+) T cells) remained unchanged regardless of the level of digestion. Histamine release of basophils from peanut allergic individuals was induced to the same extent by native Ara h 1 and its digestion products.


CONCLUSIONS
Gastro-duodenal digestion fragments of Ara h 1 retain T cell stimulatory and IgE-binding and cross-linking properties of the intact protein.
Eiwegger
T
T
Department of Pediatrics, Division of General Pediatrics, Medical University of Vienna, Vienna, Austria.
Rigby
N
N
Mondoulet
L
L
Bernard
H
H
Krauth
M-T
MT
Boehm
A
A
Dehlink
E
E
Valent
P
P
Wal
J M
JM
Mills
E N C
EN
Szépfalusi
Z
Z
D000485:Allergens / Q000276:immunology* / Q000378:metabolism*; D052179:Antigens, Plant; D001491:Basophils / Q000276:immunology; D016022:Case-Control Studies; D049109:Cell Proliferation; D003429:Cross Reactions; D016207:Cytokines / Q000378:metabolism; D004063:Digestion; D004386:Duodenum / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005512:Food Hypersensitivity / Q000276:immunology* / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D006023:Glycoproteins / Q000276:immunology* / Q000378:metabolism*; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D008565:Membrane Proteins; D010940:Plant Proteins / Q000276:immunology* / Q000378:metabolism*; D012107:Research Design; D013601:T-Lymphocytes / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D016207:Cytokines; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E