Nitration enhances the allergenic potential of proteins.
BACKGROUND
Recent investigations have shown that proteins, including Bet v 1a, are nitrated by exposure to polluted urban air. We have investigated immunogenic and allergenic properties of in vitro nitrated allergens in in vivo models.


METHODS
Untreated and nitrated samples of ovalbumin or Bet v 1a were compared for their ability to stimulate proliferation and cytokine secretion in splenocytes from DO11.10 or from sensitized BALB/c mice, and for their ability to induce specific immunoglobulin (Ig)G1, IgG2a and IgE in sensitized mice. Additionally, sera from birch pollen-allergic individuals were analysed for IgE and IgG specific for nitrated Bet v 1a.


RESULTS
Upon splenocyte stimulation with nitrated as compared with unmodified allergens, proliferation as well as interleukin 5 and interferon-gamma production were enhanced. Sera of mice sensitized with nitrated allergens showed elevated levels of specific IgE, IgG1 and IgG2a, compared with sera from mice sensitized with unmodified allergens. Moreover, cross-reactivity of antibodies against unrelated, nitrated allergens was observed in mice. We also found higher amounts of functional, specific IgE against nitrated than against untreated Bet v 1a in sera from birch pollen-allergic patients.


CONCLUSIONS
Our findings suggest that nitration enhances allergic responses, which may contribute to an increased prevalence of allergic diseases in polluted urban environments.
Gruijthuijsen
Y K
YK
Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
Grieshuber
I
I
Stöcklinger
A
A
Tischler
U
U
Fehrenbach
T
T
Weller
M G
MG
Vogel
L
L
Vieths
S
S
Pöschl
U
U
Duschl
A
A
D000485:Allergens / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D000818:Animals; D052179:Antigens, Plant; D049109:Cell Proliferation; D005260:Female; D005512:Food Hypersensitivity; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D011499:Protein Processing, Post-Translational / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D013774:Tetranitromethane / Q000737:chemistry / Q000494:pharmacology*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000187:drug effects / Q000276:immunology
D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; C061312:Bet v 1 allergen, Betula; C002744:3-nitrotyrosine; D014443:Tyrosine; D010047:Ovalbumin; D013774:Tetranitromethane