Food allergens are protected from degradation during CD23-mediated transepithelial transport.
BACKGROUND
CD23 (FcepsilonRII) is expressed by intestinal epithelial cells (IEC) following allergic stimulation and increases the uptake of IgE/allergen complexes. The aim of this study was to further analyze the role of CD23 in the intraepithelial processing of food allergens during transepithelial transport.


METHODS
Balb-C mice were sensitized intraperitoneally with horseradish peroxidase (HRP) or beta-lactoglobulin (beta-LG) in the presence of pertussis toxin. In control and sensitized mice, 3H-HRP, intact HRP, or 14C-beta-LG fluxes were measured across jejunal segments mounted in Ussing chambers, in the presence or absence of mucosal anti-CD23 antibodies. HPLC analysis of serosal buffer was performed to detect HRP- or beta-LG-derived radiolabelled metabolites generated during transepithelial transport.


RESULTS
In HRP-sensitized mice, 3H-HRP fluxes and intact HRP fluxes (3,836 +/- 476 and 290 +/- 86 ng/h x cm2, respectively) were significantly increased compared to control mice (1,677 +/- 297 ng/h x cm2, p < 0.01, and 106 +/- 23 ng/h x cm2, p < 0.02, respectively). HPLC analysis indicated the presence of intact HRP in the serosal compartment already 10 min after addition of HRP to the mucosal compartment, a result not observed in the control mice. In the presence of anti-CD23 antibodies, intact HRP fluxes were significantly decreased (131 +/- 27 ng/h x cm2) compared to control values in sensitized mice (290 +/- 86 ng/h x cm2, p < 0.02), suggesting that CD23 is involved is this 'protected' transport pathway. A similar protection during intestinal transport was observed for beta-LG in beta-LG sensitized mice.


CONCLUSIONS
These results confirm that CD23 is involved in the rapid transepithelial transport of intact allergens in sensitized animals, and indicate that CD23 opens a 'protected' transport pathway in IECs.
Bevilacqua
Claudia
C
INSERM EMI0212, Faculté Necker, Paris, France.
Montagnac
Guillaume
G
Benmerah
Alexandre
A
Candalh
Céline
C
Brousse
Nicole
N
Cerf-Bensussan
Nadine
N
Perdue
Mary H
MH
Heyman
Martine
M
D000485:Allergens / Q000276:immunology*; D000818:Animals; D001692:Biological Transport / Q000276:immunology*; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D006735:Horseradish Peroxidase / Q000276:immunology / Q000378:metabolism; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism*; D007583:Jejunum / Q000276:immunology / Q000378:metabolism; D007782:Lactoglobulins / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009924:Organ Culture Techniques; D017455:Receptors, IgE / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000485:Allergens; D007782:Lactoglobulins; D017455:Receptors, IgE; D006735:Horseradish Peroxidase