Hypoallergenic fragment of Par j 2 increases functional expression of Toll-like receptors in atopic children.
BACKGROUND
Parietaria judaica (Par j) is one of the main causes of allergy in the Mediterranean countries. The activation of Toll-like receptor 4 (TLR4) by lipopolysaccharide (LPS) inhibits nasal inflammation of atopic children.


OBJECTIVE
To examine, in vivo and in vitro, the effect of recombinant Par j 2 (rPar j 2) and of its fragments (1-55 and 52-102) on atopic children.


METHODS
We used skin prick test for in vivo evaluations. We assessed, in vitro, in peripheral blood mononuclear cells (PBMC), the effect of rPar j 2 and of the two fragments on neutrophil chemotaxis, on CD45RO, on TLR2 and TLR4 expression, on LPS binding and on interferon (IFN)-gamma release, by a microchemotaxis chamber, by flow cytometry and by enzyme-linked immunosorbent assay, respectively.


RESULTS
In vivo while rPar j 2 induced a positive skin reaction, 1-55 and 52-102 fragments did not. In vitro, while rPar j 2 increased both CD45RO expression and neutrophils chemotaxis in PBMC, both Par j 2 fragments did not. 1-55 fragment of Par j 2 upregulated both TLR2 and TLR4 expression and LPS binding, while the rPar j 2 and 52-102 fragment did not. Finally, 1-55 fragment of Par j 2 induced IFNgamma release, while the rPar j 2 and 52-102 fragment did not.


CONCLUSIONS
Hypoallergenic 1-55 fragment, upregulating innate immunity receptors and increasing IFNgamma, might re-orientate, in atopics, the immune system toward a physiologic balance between Th1 and Th2 responses.
Pace
E
E
Istituto di Biomedicina e Immunologia Molecolare, Consiglio Nazionale delle Ricerche, Palermo, Italy.
Duro
G
G
La Grutta
S
S
Ferraro
M
M
Bruno
A
A
Bousquet
J
J
Bonsignore
G
G
Gjomarkaj
M
M
D000293:Adolescent; D000485:Allergens / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000502:physiology*; D010940:Plant Proteins / Q000502:physiology*; D051193:Toll-Like Receptors / Q000096:biosynthesis / Q000235:genetics*
D000485:Allergens; C506384:Par j 2 allergen, Parietaria; D010446:Peptide Fragments; D010940:Plant Proteins; D051193:Toll-Like Receptors