Allergen specific responses in cord and adult blood are differentially modulated in the presence of endotoxins.
BACKGROUND
Endotoxins are common contaminants in allergen preparations and affect antigen-specific cellular responses. Distinct effects of endotoxin on cells in human umbilical cord and adult blood are poorly defined.


OBJECTIVE
To examine the effect of endotoxins in allergen preparations on cellular responses in human cord and peripheral blood (PB).


METHODS
The endotoxin content in beta lactoglobulin (BLG), the peanut allergen Ara h 1 and the major birch pollen allergen Bet v 1 was assessed. Proliferation and cytokine response of mononuclear cells towards contaminated and lipopolysaccharide (LPS)-free allergens were evaluated at different time-points. Fractions of contaminated BLG were generated and assayed on their immuno-stimulatory capacity. The involvement of toll-like receptor (TLR) 2 and 4 was investigated by blocking antibodies and TLR-transfected human embryonic kidney cells.


RESULTS
The proliferative response of cord blood (CB)-derived mononuclear cells towards allergen-preparations at day 3 was related to the level of LPS contamination. At day 7, proliferation was also detected in the absence of endotoxin. Cytokine production in CB was strongly affected by the content of endotoxin, TLR-4 dependent and not related to the allergen content. Allergen- and endotoxin-induced proliferative responses were generally significantly higher in CB than in adult blood.


CONCLUSIONS
Endotoxins in allergen preparations confound allergen-specific cellular responses. The impact of these contaminations varies with the blood source (CB vs. PB), the type of allergen and is time- and dose-dependent.
Eiwegger
T
T
Department of Pediatrics, Medical University of Vienna, Vienna, Austria.
Mayer
E
E
Brix
S
S
Schabussova
I
I
Dehlink
E
E
Bohle
B
B
Barkholt
V
V
Szépfalusi
Z
Z
D000328:Adult; D000485:Allergens / Q000276:immunology* / Q000494:pharmacology; D052179:Antigens, Plant / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000187:drug effects / Q000276:immunology; D004731:Endotoxins / Q000276:immunology* / Q000494:pharmacology; D005312:Fetal Blood / Q000187:drug effects / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology / Q000494:pharmacology; D006801:Humans; D007782:Lactoglobulins / Q000276:immunology* / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology*; D008565:Membrane Proteins; D010940:Plant Proteins / Q000276:immunology / Q000494:pharmacology; D013745:Tetanus Toxoid / Q000276:immunology / Q000494:pharmacology; D051195:Toll-Like Receptor 2 / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000276:immunology / Q000378:metabolism
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D016207:Cytokines; D004731:Endotoxins; D006023:Glycoproteins; D007782:Lactoglobulins; D008565:Membrane Proteins; D010940:Plant Proteins; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D013745:Tetanus Toxoid; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4
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